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A Bad Day on the Yucatan
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A Bad Day on the Yucatan

Nature Essays

A Bad Day on the Yucatan

I picture a dinosaur standing on the coast of what would become the Yucatan Peninsula. I always picture a brontosaurus, I’m not sure why, and in my mind’s eye she cranes her long neck back over her shoulder to the south-east, and up toward the sky. The gleaming object that has captured her attention is actually seven and a half miles across and is made of rock that is fifteen percent denser than the rock she is standing on, but all she sees is a gleam because it is travelling at 44,640 miles per hour and is surrounded by a shock layer that has been brought to incandescence by compression wave heating and is now at 35,500 degrees Fahrenheit, and is so bright that it is getting a little bit painful to look at. She is a brachiopod, so her encephalization quotient, which is the ratio of body size to brain size, is only 0.1. She’s not the brightest bulb in the Yucatan even by dinosaur standards, but I picture her having a very uneasy feeling about this.

The object passes over her in complete silence, being well over two hundred thousand feet above her, and in the next several seconds, as she tracks it with her tiny head and long, long neck, it burns through ever denser atmosphere, getting more and more brilliant as it plummets to the northwest, and then, at a spot fifty miles out to sea from where she is standing, it impacts.

There is a flash roughly as bright as the surface of the sun, and a reflective dome appears to rise into the sky above it and then dissipate. The sea is pulverized into a miasma along the horizon beneath it. But still she hears nothing. A widening cone of shattered rock and water rises skyward, upward and outward, in slow motion. Still there is silence, but a shimmering layer of air at ground level appears to be getting taller, and that’s because it’s getting closer—it is the leading edge of a ring-shaped blast wave moving outward at 16,700 miles per hour (I worked all this out). She gazes at its approach for long moments, and still there is only silence. It takes 10.8 seconds for the blast wave to reach her, but even then what finally hits her could not really be called sound, because sound travels at only one twentieth that speed, and besides, when this thing hits her, she does not hear or feel a thing. The impact kills her instantly, and then the heat sears the flesh from her bones.

The Gulf of Mexico is 1,500 feet deep where this great meteorite hits, which sounds like a lot of water, but it’s only one twenty-sixth the diameter of this rock. To put that another way, as its leading surface strikes the sea, its trailing surface is still at an elevation of 40,000 feet. The ocean is a mere puddle, almost inconsequential to this impact event.

The temperature at the impact site hits fourteen thousand degrees Fahrenheit, and everything within a 1,000 mile radius is immediately incinerated just by the flash. One hundred and ten cubic miles of rock is melted into a sheet three miles thick. Forests are flattened in a radial pattern out to 6,200 miles. The rock thrown skyward in the widening ejecta cone hits twenty-five thousand miles per hour in its ascent, and a lot of it ends up in orbit. Some of it even achieves escape velocity and is never seen by the planet Earth again. Some of it is on the moon today.

After the initial flash, super-heated winds race outward from the impact site at up to 2,000 miles per hour, and more forests are ignited. An earthquake of somewhere between magnitude 10 and 12, depending on who you talk to—which are magnitudes never experienced in recorded history—rocks the planet all the way from northern Canada to the mid-latitudes of South America. Oceanographic events that have been called “mega-tsunamis” hit the coasts of what are now Mexico, Texas, Alabama and Lousiana, and they are 300 feet high, but scientists figure we got off easy because the meteorite did not have much water to work with. If it had hit in deep water, the height of those waves might have been two to three miles. The ejecta that did not achieve orbit begins to fall back to earth pretty quickly, and fiery rocks rain down across the western hemisphere for hours after the impact, igniting more forests. It is the cretaceous period (actually, it is the last day of the cretaceous period), and oxygen levels in the cretaceous period were high—30 to 35 percent, as opposed to today’s 21 percent. The forests flash easily into flame, and the firestorms race in sheets across the landscape, but the inferno is limited, so far, to the Americas.

Then the orbiting rocks begin to re-enter the atmosphere.

Unlike the earlier events, the meteor shower is world-wide. The meteors, so recently blasted up into Earth orbit, start to rain down as if the sky is burning, in such numbers that they not only start spot fires everywhere they hit, but they also heat the atmosphere itself, to the point that surface temperatures reach several hundred degrees, and whole forests flash spontaneously into flame. Soot, smoke and the dust of the original explosion rise in great towers and plumes into the upper atmosphere. The sea floor of the Gulf of Mexico is now circling the globe at two hundred thousand feet. The occlusion is complete—zero light is reaching the earth. For up to two months you cannot see your hand in front of your face, and for up to a year photosynthesis is impossible world-wide. Whole food chains collapse, on a continental scale. Temperatures plummet and previously balmy areas freeze over. This “impact winter” would last about ten years, but even that isn’t the end of things.

The reason that isn’t the end of things is that those fires have also released as much carbon dioxide as three thousand years of fossil fuel burning. In addition, the carbonate and evaporite rocks of the Yucatan get vaporized by the explosion into yet more carbon dioxide, and Yucatan rock also contains a lot of sulfur, and that gets blown into the upper atmosphere as sulfur dioxide, then combines with water to create sulfuric acid. It will fall a few years later as acid rain, but in the meantime, the droplets reflect away the sunlight, contributing further to the darkening of the earth. All told, ten trillion tons of carbon dioxide, one hundred billion tons of methane gas (which, by the way, is a much more powerful greenhouse gas than carbon dioxide) and one trillion tons of carbon monoxide end up in the upper atmosphere. So as the Earth recovers from the explosion, then from the fire storms, then from the wash of acid rain, and climbs painfully, over a period of ten years, out of the dark and freezing impact winter, it is only to enter a period of global warming that would last not decades, but centuries.

What’s amazing is that anything survived.

* * * *

: The Cretacious-Tertiary (KT) Boundary Layer Photo by Mike Beauregard CC BY 2.0

Sixty-five million years later, give or take a couple, it was the late 1970’s, and a guy named Walter Alvarez was poking around near the town of Gubbio in Italy. He was a geologist, and what he was studying in Italy was the tectonics of the Mediterranean region, but what he kept wondering was a little off-topic. Why, he kept asking himself, is there this layer of unique clay exactly at the boundary of the cretaceous and the tertiary periods? The cretaceous-tertiary, or “KT,” boundary is, after all, a fairly auspicious moment in Earth’s history—it’s when the dinosaurs died. It was one of the most important extinction events in the history of life. (It was not the biggest—that was the Great Oxygen Catastrophe that gave us the air we breathe.) It had been suggested by a few lonely voices that the KT extinction might have been created by an asteroid impact, but it was a pretty fringe theory. Two geologists named Kelly and Dachille had noted in 1953 that something had hit the Earth back then hard enough to slightly alter its axis of rotation. But theories don’t go far in the scientific community until they’re backed up. Especially over-dramatic theories involving global catastrophes. No one was paying much attention. But Walter Alvarez couldn’t leave it alone. He was just sure this layer of clay held the key.

He did what I used to do when something was bugging the hell out of me: he called his dad.

* * * *

Luis Alvarez was a Nobel prize-winning physicist. He did things with people like Enrico Fermi and Robert Oppenheimer that I can’t even explain to you, including discovering whole new families of particles, but he was one of those guys who was too gifted to be constrained by his own profession, so he did a lot of work in other fields, especially during World War II. He invented “Friend or Foe” radar beacons, which are now on just about every aircraft in the world and are called transponders. (He held the patent for it, and signed it over to the government for one dollar.) He also developed ground controlled approach, or GCA, making it possible to land aircraft in low-visibility conditions, which was a pretty big game-changer in WWII. And, like most men of our fathers’ wartime generation, his work had its dark side. He invented explosive lenses. He worked out a way to keep enemy submarines from knowing they’d been found by microwave radar. And, inevitably, he ended up on the Manhattan Project, developing the atomic bomb.

: Luis and Walter Alvarez at the KT Boundary Photo courtesy of Lawrence Berkeley Laboratory, public domain

It was a brilliance that ran in the family. He descended from a long line of gifted people. His grandfather was a physician who did breakthrough work in Hawaii on leprosy. His great aunt Mabel was an impressionist painter. His great uncle Walter was a founder of the Mayo Clinic. And now his son was a little over a year away from becoming famous.

But it was physics the senior Alvarez brought to bear when his son put the KT extinction problem in front of him. The first thing the two of them decided to find out was how long it had taken for that layer of clay to get deposited. Fortunately, there’s a very convenient clock in the geological record, and it’s called iridium. Iridium is an element that almost does not exist in the Earth’s crust because it’s very heavy, and it all sank to the Earth’s core early in the planet’s history. But it exists in great quantities in all the rocks in outer space, which means in comets and asteroids, which means in all the shooting stars that burn up in our skies all the time. There is a constant light drizzle of iridium sifting down onto our earth’s surface from outer space all year, every year, and it’s quite steady and predictable. You can tell how long a layer of strata was sitting there exposed to the sky by measuring the amount of iridium in it. When they ran a sample of the KT clay, they were expecting to find that it had taken about ten thousand years to get laid down. The number that came back was four million. They were flabbergasted. There was no way that half-inch layer of clay had taken that long to get laid down. But there was another obvious explanation for all that iridium:

It was from an asteroid that impacted the earth.

: Mabel Alvarez
See page for author [Public domain], via Wikimedia Commons

Now they were really interested. They roped in two colleagues of Luis’s, nuclear chemists Frank Asaro and Helen Michel. Together, they used a technique called neutron activation analysis to identify the concentrations of all the elements in the clay. They found that the extra-terrestrial quantities of iridium were only the beginning of the revelations. The clay also contained minerals like glassy spherules, shocked quartz and micro diamonds, all of which are only created under horrific amounts of heat and pressure. And they also ran some numbers on the soot. Taken world-wide—and this layer did seem to exist world-wide—that layer of clay contained enough soot to suggest that the “entire terrestrial biosphere burned.” In layman’s terms: every plant on earth.

In 1980 they published a paper, and the shouting commenced. Some think that one reason that this debate was even more acrimonious than most was that there had not been a single paleontologist involved in this discovery. They had all been scooped by a geologist and his physicist dad. But then scientists never take major shifts like this one quietly, and shouldn’t. Arguing is what we pay our scientists for. That’s part of scientific rigor. It’s what distinguishes science from religion. They argued for a decade. What finally happened was someone found the crater.

* * * *

Actually, the crater had been found two decades earlier, it just hadn’t been announced. The data had been sitting somewhere in the archives of Pemex, Mexico’s state-owned oil company, since the 1960’s, in the form of a “gravity map,” which maps the densities of underground rock by looking at gravitational anomalies.

: Chicxulub Crater Gravity Map
The white dots are cenotes created by the impact. The white line is the coastline.
By Milan Studio.Milan studio at en.wikipedia. [Public domain], from Wikimedia Commons

The problem is that oil companies, for obvious reasons, consider their discoveries proprietary, and keep them secret.

A Pemex person named Glen Penfield stumbled across the crater again in 1978 while doing a magnetic survey of the region. He saw the arc of the crater, and laid his hands on the gravity map, and another map of the peninsula itself, and lined up the two maps. The two arcs connected perfectly. They created a great circle, half under the ocean and half under the peninsula, with the small coastal town of Chicxulub near its center. That’s next to Progreso, where the cruise ships come in, 150 miles northwest of Susan and I.

To his credit, Glen Penfield argued to make the information public, and to Pemex’s credit, they finally did allow him to present it without specifics at a conference of the Society of Exploration Geophysicists in 1981. But the talk was lightly attended because, ironically, most of the experts on impact craters were at another conference that was scheduled for the same time—a conference on impact craters. Penfield’s presentation was barely noticed. He went back to work.

The funny thing is that at almost the same time that Penfield had been presenting, a grad student named Alan Hildebrand had gotten interested in finding this crater, and was out there soliciting information on “candidate craters.” But he and Penfield did not connect until nine years later when a Houston Chronicle reporter with one of those amazing reporter’s memories hooked them up. Finally, in 1991, the dots had been connected. They had their crater.

The senior Alvarez had passed away three years before.

* * * *

: The Chicxulub Crater
By Yucatan_chix_crater.jpg: NASA/JPL-Caltech, modified by David Fuchs at en.wikipedia derivative work: Mircalla22 (Yucatan_chix_crater.jpg) [Public domain], via Wikimedia Commons

Seventy percent of species on the planet, both plant and animal, perished in this event or in the period following it. All the dinosaurs went extinct except the ones who became birds. This is a fun thing to reflect on: when you look at a cute and pretty songbird in your garden, you’re looking at the only dinosaur tough enough to survive the most horrific event in the planet’s history.

Not that evolution thinks or plans ahead, but for what it’s worth, there are great lessons in who survived and who did not. Anything large that was walking on dry land bit the dust. For them, there was just nowhere to hide. The largest vertebrates to survive were the crocodiles, for reasons that still serve them well today (they are largely unchanged): they are semi-aquatic, so they had somewhere to hunker during the worst of it. They are cold-blooded and can go long periods without food. They can get by on detritus and carrion, and they lay their eggs underground.

The same general principles applied to the creatures in the oceans. The large, surface-dwelling creatures perished, but farther down in the water column, and on the bottom, things went better, as those organisms rely more on carrion and detritus, which did not immediately vanish.

Specialists, for the most part, all went extinct. Pure predators who needed a steady supply of living prey all perished. Similarly, pure herbivores also had a rough time finding a plant for about a decade, and they all disappeared. But the generalists and opportunists who could change their habits in a pinch—those are the ones who survived.

One of them was a group of small, shrew-like, hair-covered, burrowing creatures. They were called mammals.

And that’s interesting to reflect on too. Not only did that tweety-bird in your garden survive the most hideous catastrophe imaginable—but so did you.

Now you know.

By Randy Fry|2017-10-26T10:27:53-05:00January 31st, 2015|Nature Essays|16 Comments

Finding the Monarchs
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Finding the Monarchs

Nature Essays

Finding the Monarchs

The entomological discovery of the century was made on January 2^nd, 1975 by a textile engineer with no college degree. His name was Kenneth Brugger, and his proudest professional accomplishment was inventing no-shrink underwear, which truly is a pretty proud accomplishment in my book—but he will be remembered for something far greater.

The story begins almost four decades earlier. It was 1937, and two Canadian zoologists named Fred and Norah Urquhart were obsessed with solving a mystery that had stumped scientists for over a century. In five words, here’s what the mystery was:

Where do the monarchs go?

All summer they dance and weave in abundance above the plains and hills of the United States and southern Canada. They drop into our backyards and flit around our roadsides. There are millions and millions of them. But then in the fall, they vanish, and in the spring they return. And no one could figure out where they went.

: Monarch Butterfly (Danaus plexippus)
Thomas Bresson CC 2.0, via Wikimedia Commons

Scientists knew that they were migrating. They even knew that they were overwintering somewhere in congregations, because that’s what the ones west of the Rocky Mountains do, at sites in coastal California like our old stomping grounds, the Monterey Peninsula. But the ones east of the Rockies just vanished. Every year a whole continent’s worth of butterflies disappeared. Somewhere out there, over a billion monarch butterflies were congregating together for the winter.

And nobody could find them.

: Tagged Monarch
Photo by Derek Ramsey
[GFDL 1.2], via Wikimedia Commons

The Urquharts started by attacking a fairly tricky problem no one had solved yet: How to tag a monarch butterfly. They only weigh about as much as a paper clip, and effortless flight means everything to them. How do you tag such a creature? They traveled to the Monterey Peninsula, and tested tagging methods on the overwintering population there in Pacific Grove. They endured several years of failures, and finally succeeded with a tiny self-adhesive dot-shaped label placed on the underside of the hind wing. They started tagging. After several years of grinding away at this themselves, they took it to the next level, and started recruiting volunteers, launching what today would be called a “citizen science” project. Hundreds of butterfly lovers and school children tagged thousands of butterflies every year—and they had to tag them every year, because monarchs don’t live longer than that. In that sense this was an unrelenting project they’d gotten themselves into—after seven or eight months every animal you’ve tagged is dead, and you have to start over. But they and the volunteer troops kept persevering, and the data started trickling in. The monarchs began coming back to them in the mail, some dead, some alive and lovingly packed among wildflowers in perforated boxes. They got letters. They got phone calls. One tagged monarch alighted on a golf ball an instant before the golfer smacked both of them to kingdom come. He mailed the body in. They started sticking pins in a great map. The years went by, and the flight paths began to materialize. The lines were all converging toward Texas. It was looking like a run for the border.

They started placing ads in Mexican newspapers. In 1972 Kenneth Brugger picked one of them up.

* * * *

: Monarchs Overwintering in Pacific Grove (a tagged individual is visible in upper center)
Photo by Agunther (Own work) CC 3.0, via Wikimedia Commons

Kenneth had gone through a divorce and re-crafted his life. He had quit his job working for the Jockey underwear company in Kenosha, Wisconsin, and moved to Mexico City as a textile consultant. And when he read the ad, a memory came back to him. He remembered driving once through the high elevations of the Sierra Madre mountains and suddenly finding himself inside a great cloud of monarch butterflies. He wrote the Urquharts. I think I can help, he said.

He had struck up with a Mexican woman named Catalina Aguado. He was 53 and she was 21, and she shared his love of nature. Together they began spending their weekends roaming the Sierra Madres looking for the butterflies. They had a Winnebago, and they would hike through the days and sleep in the RV. They were in frequent contact with the Urquharts, who encouraged them and advised them. They were seeing tantalizing signs—a transient cloud here, a roadside littered with bodies there. The signs were pointing toward Michoacan state. They talked with locals. They continued looking. In 1974 they got married.

The moment finally came when they were climbing a peak called Cerro Pelon. They ascended past the 10,000 foot level and crossed a clearing toward a stand of oyamel fir trees, and when they drew close they realized that every tree was cloaked in monarch butterflies. I picture them both standing speechless. The butterflies hung in festoons from every bough, they covered every trunk, they carpeted the ground, and clouds of them danced through the air in front of their faces. Fred Urquhart remembers getting the call. “We have located the colony!” Kenneth said. “We have found them—millions of monarchs—in evergreens beside a mountain clearing.”

I am certain that that scene was, to Kenneth Brugger, a spectacle of breathtaking beauty which he never forgot, but actually, the orange of the butterflies was not something he could see. He was completely colorblind.

* * * *

: Monarch Butterfly Biosphere Reserve
By Luis Avalos (Own work) [CC BY-SA 3.0], via Wikimedia Commons

Really, Kenneth Brugger solved two mysteries. Indigenous peoples in those mountains like the Purepecha, the Otomi and the Mazahua knew all about those monarch colonies. In fact, they revered them. The monarchs were part of their folklore and their spirituality. They rang the church bells when the monarchs arrived, usually around the Day of the Dead, and they considered them to be the souls of their ancestors. They knew all about those butterflies, but they didn’t talk about it much to outsiders. And they didn’t know where in the heck they disappeared to in the spring.

They all got their lives changed by this discovery. They now live in the middle of a World Heritage Site called the Monarch Butterfly Biosphere Reserve, amid throngs of tourists.

* * * *

: Monarchs at the Monarch Butterfly Biosphere Reserve in Michoacan, Mexico
By Bfpage at en.wikipedia [Public domain], from Wikimedia Commons

The monarchs cannot overwinter just anywhere. They’re extremely particular. The area must have trees to roost in, whose foliage and canopy protects them from direct snow and wind. It must be close to freezing, so that their metabolisms slow and they don’t use up the reserves they will need for the return flight. But it cannot be too cold, or they will have to turn on the furnace to keep from freezing to death, and that uses up reserves too. There must be underbrush for safety, because when they fall to the ground, which happens a lot when it’s close to freezing and you’re in a stupor, it is usually too cold for them to fly back up to escape predators like mice, but they can crawl up into the understory. It must have streams or some other water source to drink from, and it also must have fog, again to keep them hydrated, because they can only fly to the water source during warm hours on warm days, and they must return to the roosting tree before it gets too cold to fly, and they get very jumpy about that. Sometimes you can watch an entire cloud of monarchs rise from a water source all at once and return to the trees, just because a cloud has passed in front of the sun.

In Mexico, all these requirements limit them to just a dozen small oyamel forests in the Sierra Madres, which occur on a few mountain tops, above 10,000 feet, and facing southwest. So there is great concern about the deforestation that is happening, due to illegal logging. But let me mention here that the locals who do that are subsistence farmers living on communally-owned “ejito” land and have been relying for generations on these forests for lumber and firewood. It’s up in the United States that monarch habitat is being wiped out systematically by huge corporations, and it’s a much more dire problem. More on that in a bit.

* * * *

As spring approaches and the days get longer and warmer they begin to get restless, and clouds of them fill the air. The males pursue the females up into the sky and grapple with them, pulling them in long, fluttering paths to the ground, where they mate, remaining attached for up to an hour. They have not eaten since they arrived in the fall, and they have a long journey ahead of them. Mated females begin leaving first, usually the second week of March, and it has to be timed perfectly. If they leave before the milkweed has sprung up in the U.S. and Canada, the cycle will fail, because they have to lay their eggs on milkweed. Nothing else will work for the caterpillars when they hatch.

The females make it about halfway up the United States, laying eggs in milkweed patches all along the way, and then they die. The males don’t make it as far. They start dropping right away. Unromantic fact: Evolution doesn’t usually knock itself out prolonging the life of a male who has already mated. We become superfluous. (In some cases we become a protein source for the female, but monarchs don’t do that.)

The eggs hatch and within five weeks there is a new wave of monarchs, and they fly north, continuing the migration. This generation might make it as far as southern Canada, and again, they are laying eggs on milkweed patches as they pass, sending new waves of monarchs into the skies across the North American landscapes. There will be a couple more generations like this through the summer, and finally the whole continent is repopulated, shimmering and glinting with monarchs again, and then something interesting happens. When the very last generation emerges from their chrysalises in late August or early September, they have developed differently. Their wings are slightly larger. The veins in their wings are thicker. Their bodies are heavier and can store more fat. They will live for seven or eight months instead of a few weeks. Their sexual maturation has been put on hold. These butterflies are not about mating, they are about flying. That’s because the trip south is not a multi-generational affair like the trip north was. They’re in this for the long haul. For some of them it will be over three thousand miles—then they must survive the winter, then they must fly most of the way back. These are the elite athletes, the ultra-marathoners. These are the super-butterflies.

And the amazing thing is that these are the great-great-grandchildren of the butterflies who left the Sierra Madres. Not a single butterfly in this migration has ever flown the route before. And they’re going to find a small grove of trees thousands of miles away in the middle of a mountain range they’ve never seen. Scientists haven’t cracked that one yet. No one knows how they do it.

They only fly during the day. They roost in trees at night, at what are called waystations, in smaller congregations than the final one, but still a delight to behold. As they move south and converge toward the border, the ribbons of butterflies in the sky thicken and broaden, and there are places in Texas where the sight can take your breath away.

: Monarch Caterpillar
Photo by Linda Tanner, [CC BY 2.0], via Wikimedia Commons

They don’t have many predators. One reason for their fondness for milkweed is that it contains chemicals called cardenolides, which are steroids that taste nasty and arrest your heart, and the caterpillars not only eat it without getting poisoned, but they proceed to co-opt the chemical, and put it to use in their own systems as a defense against predation, and it persists into the adult butterflies. Both caterpillar and butterfly have bold markings that are considered warning coloration. The viceroy butterfly (Limenitis archippus ) looks almost identical to the monarch, and I was taught growing up that it was a case of Batesian mimicry, and the viceroy was getting a free pass while not really being toxic himself. But there is now evidence that the viceroy is even more toxic than the monarch, which actually makes it a case of Mullerian mimicry, in which both species are dangerous, and have found it advantageous to advertise that fact with the same signals.

Here’s the bad news: In 1996 a little over a billion butterflies overwintered in Mexico. In 2013 there were thirty-three million. That’s a drop of 97%. According to a non-profit called Journey North, there is a whole range of causes, including the deforestation I mentioned, a series of unfortunate climatic events, ordinary loss of habitat due to development, and even ecotourism isn’t helping. But the problem that really frosts me is the one about the milkweed, because that’s one which, at least in theory, we could fix if we wanted to. Here’s what’s going on:

There are 115 species of milkweed, and the monarchs can use any of them. They grow like weeds in a variety of habitats from swampy to arid, and they do well on roadsides, field sides and other disturbed areas. You’d think there would be worse plants to hitch your wagon to. But what happened to the monarchs is genetically modified crops.

There are now genetically modified corn and soy bean strains in wide use which are resistant to an herbicide called glyphosate (you know it by its brand name, Round-Up). This allows the agriculture industry to spray it liberally on their fields, where it neatly kills everything but the crops. The problem is, the vast majority of monarch habitat had been in the sprawling farmlands of America, especially the corn belt. It was between the rows of crops, around the edges of fields, hugging the fence posts, in odd corners behind sheds and structures—milkweed is one of those plants that pops up in any unused space in the agrarian landscape. And according to Monarch Watch, the Midwest monarch habitat is “virtually gone,” with 80 million acres lost in recent years. Dr. Chip Taylor remains upbeat. “Numbers are really down,” he says, “but the monarchs will come back.” And I’m glad Monarch Watch has an optimistic director. We need optimists.

If you want to help, you can plant a monarch garden. Monarch Watch can set you up with a monarch garden kit, and show you how to plant your own little monarch waystation habitat with milkweed for the caterpillars and all the right wildflowers for the adults.

* * * *

It seems like way too many of my articles have a sad ending. But I believe in looking at the joy when we can, and the story of finding the monarchs is a captivating and uplifting drama. It was many years ago now. Of the four players in the tale, only Catalina is still with us, but all of them will be remembered. So that’s the image I’ll leave you with: Catalina Aguado and Kenneth Brugger walking out into a high-altitude clearing in the Sierra Madres, and staring in stunned silence at millions and millions of beautiful monarch butterflies.

Now you know.

When Squids Fly

In this article I’m going to not tell you about cuttlefish.

We had dinner with Dave, Nancy and their daughter Sidney last night, here on our Caribbean coastline in Mexico, and all of us were remarking on the cuttlefish we’d been seeing out on the reef lately. Cuttlefish are beautiful and enchanting little creatures, about nine inches long, with graceful tentacles hanging from their face, huge, mesmerizing eyes with W-shaped pupils, and an apron-like fin all the way around their body that undulates like a dust ruffle to propel them around. They’re inquisitive, and whenever Susan and I come across a few, they will usually stay with us for a while as we swim. Caribbean reefs are just full of beautiful and mysterious creatures, but Susan and I were becoming especially fond of these cuttlefish.

The specific question that had been intriguing Dave was why they always seem to occur in threes. Susan and I had noticed this too. You’ll see them in ones and twos now and then, but usually threes. Fascinating. I started digging. What I learned was just amazing. Here’s what I found out:

Cuttlefish don’t occur in the Caribbean.

“D’oh!” I said to my laptop monitor, and smeared my hand down my face. It shows you how much I still have to learn about my new ecosystem.

No one’s sure why they don’t occur in the Caribbean. Cuttlefish have one of the strangest distributions you can imagine. They’re in the Atlantic and they’re in the Pacific—it’s not like they’re not in our oceans. They’re on the European coastlines and the African coastlines and the Asian coastlines and even the Australian coastlines, but they do not touch the Americas. The best guess is that they evolved in the old world, and then the big oceans got too cold and deep for them to cross, being warm water and shallow water creatures. There’s a part of me that’s somewhat surprised that they haven’t managed to get introduced somehow, and start throwing things out of whack like the lionfish is doing.

What we’ve been looking at is called the Caribbean reef squid (Sepioteuthis sepioidea), and they look a lot like a cuttlefish—in fact, their scientific name alludes to the resemblance (cuttlefish being the order Sepiida).

Well, they may not be cuttlefish, but they are cephalopods, and cephalopods are my second-favorite mind-blowing organisms after jellyfish, so Dave, don’t be disappointed yet. Trust me, Caribbean reef squids are fall-down-and-slap-the-ground amazing. For one thing, they can fly. More on that in a bit.

Cephalopods are the octopi, squid, cuttlefish and nautiluses. They are a mash-up of legacy evolutionary traits and astonishing innovations not seen anywhere else. They’re shellfish (mollusks) who took a bizarre evolutionary turn, and I hugely enjoy bizarre evolutionary turns, because they remind us that life on this planet is not following any grand scheme, and neither are we. (We became us by accident too, believe me—and by the way, we only made it by the skins of our teeth.)

: Caribbean Reef Squid (Sepioteuthis sepioidea) Photo by Nhobgood Nick Hobgood CC BY

Cephalopods can change color in a flash, by conscious control, using muscular contraction and pigment cells called chromatophores. Their colors shimmer and dance across their bodies as you watch. They can also change their texture instantaneously, going from silky smooth to rough and spiky in a blink, and they can change their shape to mimic other creatures or objects. All that remains of their shell (ignoring the nautilus for now) is a beak a lot like a parrot beak, which is dead center between their tentacles (actually called arms) which they use to crunch the shells of their prey. A large species of octopus can have roughly the intelligence of a dog or a cat, depending on who you talk to, and squids and cuttlefish have been studied less, but appear not to be far behind.

That intelligence level is not bad for a shellfish, and it fascinates scientists, because their brains and nervous systems are so radically different from our own, or from any mammal, or even bird or reptile. They are such different creatures that in many ways intelligence in cephalopods can be considered a case of convergent evolution. That’s where two species independently arrive at a similar solution to a problem. Two thirds of their neurons are not even in the brain, but are out in the arms, which have a lot of autonomy in what they do. It is not a centralized system like ours, and if you watch an octopus forage in a rocky reef, you’ll see this design at work—they are reaching into numerous crevices and hidey-holes simultaneously. Clearly they’re thinking about eight things at once.

: Two Caribbean Reef Squids (in different moods)
Photo by Clark Anderson CC BY-SA 2.5

You can put a crab in a jar, and an octopus will figure out how to unscrew the lid and get it out. You can put the octopus in the jar, and he’ll figure out how to open it from the inside. I don’t know if they’ve tried any of this with a squid or a cuttlefish. An octopus named Otto in the Sea Star Aquarium in Coburg, Germany, got annoyed at the 2,000-watt spotlight that was left on all night above his tank, so he started hitting that thing with jets of water and shorting the place out. I’m not making this up. It threw the aquarium into crisis. Everything went down including the pumps, and it threatened the lives of all the creatures in all the tanks, and it happened every night. They had to stake the place out to figure out what the hell was going on. Otto had other quirks: He was fond of doing something a lot like juggling with the hermit crabs in his tank. He would periodically rearrange everything in it (including the hermit crabs), and he liked to damage the glass by smacking it with rocks. There are other stories from other aquariums. They are talented escape artists, and will leave their tank at night to help themselves to dinner in the crab exhibit, returning to their own tank to eat, and then hiding the remains.

But the thing is, they don’t live long. Sophisticated and intelligent though they are, one or two years is all you get if you’re a cephalopod. It’s called being semelparous—they die immediately after they reproduce, and there’s not a thing you can do about it, and I remember this causing a lot of wet eyes around the Monterey Bay Aquarium from time to time when I was a docent there. These creatures are aware, and they have personalities, and attachments get formed—and then they die.

* * * *

In 2001, Sylvia Macia and her husband Michael Robinson, both marine biologists, were in a boat off Jamaica when a Caribbean reef squid burst out of the water with its fins flared outward and its arms held in a radial pattern, and it sailed to a height of six feet above the water over the course of a thirty-foot flight before dropping back in. They were flabbergasted. Flying fish do this (family Exocoetidae), and it’s a cute trick for predator evasion. There’s no better way to befuddle your pursuer than to blast through a reflective ceiling and vanish. But squid? There had been a few rumors and folk tales, but hell, the ocean is just full of rumors and folk tales. Thor Heyerdahl, who has (and deserves) some respect, reported squid occasionally falling on his raft Kon Tiki. And now and then a biologist will find a squid dead on the floor next to his tank. But those kinds of jumping mishaps can happen with any fish, including a goldfish. This thing was flying.

They sent out a signal to the mollusk community. Reports started trickling in. Maybe this had been witnessed before, but people had assumed they were looking at flying fish. I mean, let’s face it, a flying squid is just not something that has a cubbyhole in your brain. But Macia and Robinson were marine biologists. They knew what a Caribbean reef squid was. Aware of the possibility now, scientists began paying attention with new eyes. The sightings continued to mount. But they were all anecdotal. There were no photographs. There was no proof. The sightings seemed to be very rare, and the flights are so brief, and squid are nocturnal, and catching a flight on film was looking like it might be impossible. They published a paper anyway, in 2004. It was well received. But they still had no proof.

Then, in 2009, a retired geologist named Bob Hulse was on a cruise ship off Brazil. He was an amateur photographer, and he was packing a wildlife camera a lot like Susan’s. He was shooting in burst mode, and at a high resolution, and he captured a handful of “unusual creatures” flying above the water. Though it was not his field of science, he was observant enough to know that he was seeing something weird. He forwarded the shots to the University of Hawaii, and they forwarded them to a scientist named Ronald O’Dor, now at Dalhousie University in Halifax, Canada, and that’s who started working with the best and, at the time, only photographic documentation of flying squid. (They have since been photographed off Japan.) He knew the data he was looking at was gold. The exact interval between the frames was known, and he could calculate the velocity and the acceleration, and get a close look at the body parts. He lit into the project.

What O’Dor is piecing together is amazing. Cephalopods already have the jet propulsion thing dialed in. That was known. They jet around underwater, and blast away backwards as an escape technique. They fill their body (mantle) with water and force it out under great pressure through an organ by their mouth called a funnel. The funnel can be directed, like the nozzle of a guided missle, so they have control. They extend their fins, and hold their arms out stiffly to create another flight surface, and they rocket through the air like little cruise missiles, trailing exhaust streams of water and steering with their flight surfaces. Gliding is too tame a word for what they do. They have a propulsion system onboard, and they have aerodynamic control.

This is breaking science (he presented his paper in 2012), so there is still lots of argument, but O’Dor now believes that they do not fly to escape predators—they do it to travel long distances. They do it to escape the drag of the water. He believes that it explains some long migrations that had always seemed implausible. Using Hulse’s photographs, he calculated that they get five times the speed in the air that he had ever measured in the water from the same propulsive effort. They fly. They fly to get around. But we never knew they did it, because they do it at night, when the birds aren’t out.

Six species of flying squid have now been identified.

The Caribbean reef squid was the first.

* * * *

The Caribbean reef squid communicate with each other through color. Over forty distinct patterns of color and shape have been identified, and that’s just for communication. There are looks scientists call bars, belly stripes, dark arms, yellow flecked, speckled belly. When they’re pissed off, their brow ridge turns metallic gold. They layer the artwork, like imaging programmers do. There will be a background, and then one or more patterns or shapes overlaid on top of it. Scientists have modeled the whole thing in Photoshop, and given them names. They can flash one message to a squid on their right, and a different one to a squid on their left. The courtship display is a shimmering, moving background overlaid with zebra stripes. Some scientists are arguing that they have both a vocabulary and a syntax, and that that constitutes language. But only a few are saying that. Language in animals is controversial. It takes cojones to use the L-word in the scientific community.

They can imitate anything. When they flee into open water they become pale. When they flee into the coral they become rough-textured and brown. When they’re stalking prey they can make themselves look like sargassum seaweed. They can become a parrotfish by swimming backwards, holding their arms out like a tail and displaying eyespots on their rears. Like all cephalopods, they can shoot out a cloud of ink to confuse a predator, and sometimes they’ll do this and then real quick make themselves look like an ink cloud next to the ink cloud.

They are very social. They hang out in schools called shoals, and there is a hierarchical social structure, based mostly on size. The shoal will have sentinels around its perimeter, all facing outward in different directions. If a predator needs to be distracted or confused, one of the larger squid will rise to the challenge. Mixed schools have been observed, with other species of squid present, and there is an association with two species of goatfish, who will forage on the bottom beneath the shoal of squid, protected by their vigilance, but it’s not clear what if anything the squid get out of it.

The young hide in the turtle grass beds, and the older ones like to shoal in the open water, and here, Dave, I’m circling back to your question. When they come into a reef, it’s usually to mate. To get the girl, a male must intimidate and out-display other males, and these face-offs will be going on in the coral, always in the presence of a female. Two plus one makes three. I’ll bet that’s what we’re seeing.

In the end, the winner approaches the girl. At first she flashes an alarm pattern at him, but he persists, comforting her by blowing water across her, jetting away briefly, and then returning, in his shimmering, zebra-striped splendor. This might go on for an hour. Finally, when she has succumbed to his charms, he displays a special pulsating pattern and attaches a sticky packet of sperm called a spermatophore to her side, and leaves.

So in the end, it is she who performs the sexual selection for the species, choosing whether to use the spermatophore. She can place it herself into her sexual organ, called a spermatangia–or she can discard it. If she has deemed the male to be worthy of continuing his evolutionary journey, the next thing she does is find a place to lay her eggs. Then she dies. She never meets her children.

Now you know.

Absurd Beaks and Materials Engineers

My principal question was this: When a toucan tries to fly, why doesn’t he end up planted in the ground like a lawn dart?

And when I thought slightly more seriously about this, I realized that I had several other questions about the toucan as well. How did that beak happen? Why would such a thing evolve and what is it for? If it doesn’t pull him straight toward the ground at thirty-two feet per second squared, how does that engineering work? It clearly has enough strength to take the beating any beak has to take. It must weigh something.

As children, toucans were probably among the first five or so birds we all learned the names of, but I was realizing that I know almost nothing about them. So I am setting out to change that. Who are these beautiful birds with the absurd beaks?

And there is another reason I’m writing this, and it has to do with the fact that I’m a birder. I’m not a great birder, but I am a birder, and birders are an odd lot. I’ll tell you something about us: There is a handful of birds out there which are so iconic that any birder will simply never forget his first sighting. I remember my first bald eagle (Alaska, 1984), my first peregrine falcon (kayaking off Big Sur, 1991) (I got so excited I almost capsized and drowned), and my first flamingo (Celestun, Mexico, 2007).

And Susan and I both saw our first toucan in November of 2007 in a jungle fifteen miles southwest of where I’m sitting right now, and here’s the personal connection: Early next month we’ll be moving to that jungle. That very spot. We were looking at property at the time, and now we’re buying it. Five acres, with an off-grid home. Toucans will be a regular part of our lives.

It’s time to learn something about them.

* * * *

: Keel billed toucan (Ramphastos sulfuratus) on a neighbor’s property.
Photo by Jim Fossheim.

The argument about what the beak is for has been going on for about a century and a half, and it’s showing few signs of resolution. The first theory came from The Man himself: Charles Darwin was convinced that the toucan’s beak was for a sexual display. That’s been discredited, but I can see why he went there. Most absurd things you see in nature are about sex. (Most absurd things you see in the human race are too, but that’s off-topic for a Ranger Randy article.) It’s a known phenomenon, and it even has a name: It’s called sexual selection. That’s what they call it when a trait evolves which contributes absolutely no survival value, but does help the organism attract a mate and reproduce more successfully. The example they always use is the tail of the male peacock. But the problem with the toucan’s beak is that both sexes have one, and they’re identical. That almost never happens in courtship display adaptations, especially in birds. Almost always, it’s only the male who gets weird. The female tends to stay subdued in appearance and practical in design, because she has an actual job to do—she has to bear those children and raise them, and she may or may not be a species lucky enough to get any help in that from the male.

The next theory I ran into was that they have those outrageous beaks because they eat fruit. Well, okay, they are fruit eaters (frugivores) but the problem I have with that theory is that the forest is just full of fruit-eating birds who have perfectly ordinary-looking beaks. Orioles come to mind.

: Hooded Oriole (Icterus cucullatus)
By U.S. Fish and Wildlife Service Headquarters
[CC BY 2.0], via Wikimedia Commons

It was suggested on the National Geographic website that the beaks allow them to reach fruit farther away from themselves on branches that wouldn’t support their weight. Sorry, I’m not convinced by that one.

Another suggestion was that by reaching farther away for fruit without having to move, they are conserving energy, and improving their calorie mathematics. That one didn’t sell me either.

Some have suggested that the beak intimidates predators and competitors. Well, if so, it’s all show, because the beak is not strong enough to be used as a weapon, and toucans don’t fight with them.

It’s been proposed that they can reach farther into tree cavities for food. It’s been proposed that it helps them plunder hanging nests (they can be egg-stealers).

And the scientific community was all abuzz in 2009 because Glenn Tattersall of Canada’s Brock University did a very interesting study and proved that the beaks are used for heat exchange. They are well-supplied with blood, they are not insulated by feathers, and the toucan can regulate the blood flow to radiate away more or less heat and regulate his body temperature. A wave of exuberant articles hit the popular press. The British paper The Independent crowed, “Mystery of the Toucan’s Beak Solved.”

Well, I beg to differ, and so does the author of that study. There is a difference between what an adaptation is currently used for, and why it evolved. If you actually read the paper in Science Magazine, Tattersall himself says that the evolutionary forces that led to the beak “remain elusive.” That said, it was a wonderful and important study, and he did conclusively prove, in an ingenious way, that they thermoregulate with their beaks. (This is what jackrabbits’ ears are for also—they have nothing to do with hearing.) But it could easily be what scientists call an exaptation—something that evolved for one purpose and then, down the line, got used for another. A perfect example of an exaptation is bird feathers. They originally evolved for insulation, and only later were adapted for flight.

Now, I want you to bear in mind that I’m an amateur naturalist. My estimation of this situation is not going to stop very many great minds in their tracks. But for what it’s worth: I don’t think we’ve figured this one out yet.

As you probably guessed, the beaks are very lightweight. That’s why there’s no lawn dart phenomenon. The inside of those beaks is a three-dimensional matrix of tiny little struts, a sort of latticework, but in 3-D. (The insides of our bones look like this too.) The result is that although the beak is a third of his body length and up to fifty percent of his surface area (which is why it’s a great radiator), it is only a twentieth of the bird’s mass.

But in the case of the toucan, evolution has added another innovation to this design which has the engineering community all abuzz. A materials scientist and aerospace engineer named Marc Meyers, at University of California, San Diego, looked into the design of the toucan’s beak, and found that as well as having that 3-D matrix of little struts, which are pretty common in the animal world (they’re called traberculae), there are also membranes spanning each space created by them, like little drum skins. It is as if the whole structure had been dipped in a soapy liquid and allowed to dry. This adds another whole dimension to the strength of that beak, because now what you have is struts carrying compression loads, and membranes carrying tensile loads, and if you’re not familiar with those terms, they’re pretty much what they sound like. (I know them because Susan hung out with a lot of architects for most of her career.) Compression strength means it resists being compressed. Tensile strength means it resists being pulled apart. A rope has high tensile strength and zero compression strength. A stack of bricks is just the opposite. The toucan’s beak has both. But it gets even better, because there’s a third effect as well: The cells created by the membranes are airtight, so there is also cushioning from air pressure, like closed-cell foam rubber. It’s looking like this design is unique in the bird world, and Meyers is advocating getting some technology-imitating-nature stuff going on this, because he is really impressed with the strength-to-weight ratio of these beaks, and also with the complexity of the ways it absorbs force and resists damage. He thinks there could be lots of applications for it.

: Gregarious, social and playful: A family of keel-billed toucans traverse the canopy.
Photo by Jim Fossheim

The toucan we see most often around here is the keel billed toucan (Ramphastos sulfuratus), and it’s been delightful to learn a few things about them. They’re very gregarious, very social and very playful, and they enjoy tossing things back and forth to each other (they’re quite dextrous with those beaks). One of their courtship rituals is a fruit toss, in which male and female flip morsels of fruit into one anothers’ mouths. They travel around in small family groups of six or twelve, and they’re actually not the greatest flyers. They’re a deep forest bird, with stubby wings, and they prefer hopping to flying.

Hopping, however, is something they’re very good at, and since they stay mostly in the upper canopy, which is very contiguous in a tropical forest, they can roam a long way just by boinging from branch to branch. They nest colonially in tree cavities, and that cracks me up. It seems like every time I write an article, at some point I come across something that makes me laugh, and this time that’s what it was. Think about this: Space is tight in your basic tree cavity, and they’ve got those humongous beaks. So they have a trick when they settle down at night, in which they tuck their beak completely under themselves, and wrap their tail, which is basically double-jointed, forward over it, and become a little ball of feathers.

The young take eight to nine weeks to fledge (grow up), which is longer than most, and the main reason for the delay is that is that they have to grow that beak. They’re not born with it. It would never fit in an egg.

And yes, the female does get help from the male in child-rearing.

And I’ll leave you with one more important fact: According to the expert breeders at Emerald Forest Bird Gardens in California, toucans hate sugary breakfast cereal. Never touch the stuff.

Now you know.

A Well-Defended Tree

On the path that runs from Dave and Nancy’s back porch to the Yal Ku Lagoon there is a small, unassuming acacia tree. I’ve brushed past it hundreds of times. It is a perfectly ordinary looking acacia tree—pleasant to look at, shades the trail nicely, lovely when it blooms—but man, you’d better be nice to it, because it is the most well-defended tree on the property. In fact, it is defended by an army. An army of ants.

I love symbiotic relationships. If there’s anything that fills me with wonder more than organisms do, it’s the relationships between them. And this one will blow you away, I promise.

The acacia is Vachellia collinsii, commonly called the swollen-thorn acacia, or the hollow-thorn acacia, and those thorns are so wicked that one punctured my truck tire once. The thorns are hollowed out and occupied by one of a couple of species of ants. The ants are in the genus Pseudomyrmex, and I tried to figure out which species we have back there, but they’re too little and too mean and I gave up.

: Ants patrol Dave and Nancy’s acacia. The beltian bodies are visible on the leaf tips.
Photo by Randy Fry

They nest and raise their larvae in the hollow thorns, but providing shelter is not all this tree does for them. It also feeds them. In fact, it feeds them carefully and generously, and with a diet tailored to their needs. There are little nubs at the bases of the leaves called extrafloral nectaries which exude a sweet nectar and keep the adult ants well fed, but then at the tips of the new leaves there are also little pods called beltian bodies which are rich in protein, and the ants nip those off and feed them to their larvae.

: My truck tire impaled by an acacia thorn
Photo by Randy Fry

What does the tree get out of it? Well, let me put it this way: You are looking at a tree that never has to worry about herbivore attack. And if you’re a gardener you’ll know what a game-changer that is. Just about every other plant in the world is plagued by insects from aphids to grasshoppers to mites to worms to caterpillars, not to mention the larger herbivores like mammals and reptiles…yet here this acacia tree serenely stands—in the middle of a tropical forest where the insect life is grandiose in its proportions—and it’s completely unscathed. It has even stopped producing the chemical defenses against herbivore attack that other acacias use (alkaloids and cyanogenic glycosides), and it does not even have to toughen its growing leaf tips like other plants do, with the result that it can grow a lot faster and out-compete its neighbors.

The ants attack leaves as well as herbivores. Any leaf of a different species that touches an acacia leaf gets quickly clipped away. The acacia tree looks like it’s nestled in comfortably against its neighbors, but if you look closer you’ll notice that not a single leaf of a neighboring tree is actually touching an acacia frond anywhere. Often the ants even keep the ground clear around the trunk of the tree. I’m not making this up. There are signs of it around Dave and Nancy’s tree. They weed around it, preventing any other plants from getting established and competing for the water and nutrients. This acacia lives a charmed life. It doesn’t have a thing to worry about, not even competition. This acacia lives in a patrolled, gated community. Nothing goes on in that tree without the permission of the ants. All the tree has to do is sit there and grow.

: It is probably the ants who are keeping this area clear of weeds
Photo by Randy Fry

What’s interesting, though, is that the ants do not attack absolutely everybody. I had this article half-written when Susan and I went walking around the Coba ruins yesterday and saw a wasp nest in a hollow-thorn acacia. We looked at each other and blinked. “Huh?” we said in unison. We checked for the ants. They were there alright. We walked on, and saw a few more wasp nests in a few other acacias. This was not random chance. It was a preference. I came home and did some more digging. The wasps paint the touch points with a chemical that deters the ants and keeps them out of the nest. The wasps like it because they are protected from predators by both the thorns and the ants. (Yeah, I know, it sounds like an unpleasant bit of foraging to me, but there are animals who will tear up a wasp nest to get the grubs.)

Birds also build nests in hollow-thorn acacias, and love it there for all the same reasons the wasps do, but it is “not yet clear” why the birds do not get attacked.

: A wasp nest in an acacia at the Coba ruins
Photo by Susan Fry

One reason for this “not yet clear” stuff is that hollow thorn acacias have not been well-studied historically. First of all, I can attest that those ants do not like naturalists any better than they like herbivores. But also, back in the day, botanists did all their field work with plant presses, and those thorns can really screw up a good plant press, and on top of that you end up with a plant press full of extremely vindictive ants. They’re not the most pleasant trees to study, and I’m looking forward to moving on to my next article.

There are a few downsides to this system, though. The acacia gets pollinated by bees, and the bees must avoid the ants, though they seem to manage it okay. Also, the acacias do not colonize new areas well, because both tree and ants have to move together. This is, after all, almost a full, two-way symbiosis (it’s called an obligate symbiosis). The ants cannot survive at all without a host acacia, and as for the acacia, well, it does not survive well without the ants, because it has no other defense against herbivores. An acacia seedling in a new area must wait about nine months before it can hope to get befriended by an ant colony, so it gets hammered and weakened by the bugs, and then, without its army of tree pruners, it gets covered over and shaded out pretty quickly. That’s why it reproduces mostly via suckers from its roots, where it can immediately benefit from the neighboring ant colony. An ant colony can span several trees, because they have multiple queens, making them what computer programmers call “scaleable.”

They did some studies on ant-acacia partnerships in Africa and discovered that if you fence off the acacia to protect it from large herbivores, it scales back its production of nectaries and thorns because it no longer needs the services of the ants. I kid you not. It lays them off. But it sort of backfires, because then the ants have to find another way to make a living, so they go back to farming aphids like their ancestors did, and end up not only allowing these plant-eating aphids in the tree, but promoting and protecting them.

: Bagheera kiplingi
Photo by Randy Fry

Here in Central America there is one creature who has learned to game the system. He’s a small spider, and he’s kind of cute (for a spider). He’s called Bagheera kiplingi, and if you’ve read some Kipling you’re probably chuckling right now. Yes, he was named after the lithe and agile black panther Bagheera in Kipling’s Jungle Book stories, because he’s a member of a family of lithe and agile spiders called jumping spiders (family Salticidae). But he was named back in the late 1800’s and the scientist who named him had only a single dead specimen and no idea what it did for a living, so he missed out on one of the most entertaining ecological stories in spiderdom. It wasn’t until 2001 that people from the University of Arizona started coming down to the Yucatan and studying this thing in situ, and here’s the scoop: There are 43,678 species of spiders described by science, and this is the only one who is vegetarian.

He lives on the nectar from the extrafloral nectaries that are there for the ants. And boy, do the ants hate that. Those ants really want to kill him, but they can’t catch him because he’s a jumping spider. He spends his whole life in that acacia tree surrounded by ants who want to kill him. He brings to mind that iconic line delivered so masterfully by Jack Nicholson, playing a Marine Colonel in A Few Good Men. I can almost see that Nicholson grimace as he says, “I eat breakfast three hundred yards from four thousand Cubans who are trained to kill me.” That’s what it’s like for Bagheera kiplingi, but they can’t lay their mandibles on him because he’s capable of amazing athletic feats. He leaps from thorn to frond to thorn to avoid them, and he spends his down time on old, dried-up parts of the tree that are not patrolled. But every now and then, when an ant is strolling by carrying a larvae, he’ll mug that sucker and steal the larvae and eat it. It’s the only time he eats meat, and I think he only does it for retribution.

The jumping spiders in general are also a pretty good yarn, so I’m going to allow myself one of my tangents at this point. There are about five thousand species of them, and the other 4,999 or so all use their athletic skills to ambush prey insects. They are known for having excellent eyesight and high cognitive skills (for a spider). They don’t use muscle contraction in their leaps, they use hydraulic pressure, which is why they don’t have gigantic hind legs like a grasshopper. They have four pairs of eyes, giving them almost 360-degree vision, and the center pair (called the anterior median eyes) have a very narrow field of vision, but they have good depth perception. If you’re an insect and he wants to jump you and eat you, he will turn the front of his body toward you to bring those anterior median eyes to bear, then he’ll round on you with the rear abdomen and legs, and then he’ll creep up, step by step, a lot like your house cat stalking a bird. Finally, the last thing he does before the pounce is attach a strand of silk where he’s standing. They call it a drag line. If he misses or things get messy, he can climb back up to where he was, and it also helps him hold his position when he attacks something bigger than he is. But they can use it even more creatively than that. Sometimes they will attach the drag line in a different location, so that it alters the trajectory of their leap. They can even use this technique to nail an insect who is on an inverted surface.

: Pretty, for a spider: A male peacock spider (Maratus volans) does a courtship display
By KDS444
[CC BY-SA 3.0], via Wikimedia Commons

They are known for traversing complicated routes to get in position for an attack, and sometimes the route even takes them out of sight of the prey for a period, which suggests that they have a pretty good memory on board. They’ve been observed descending from one bush and climbing back up a neighboring one to get at a prey insect, and that kind of detour solving is just way more brain power than scientists can explain in a creature this size.

And man, you should see their courtship displays. They rival the displays of peacocks and birds of paradise, with shimmering, iridescent blues, reds and yellows, and elaborate dances. They’re really quite beautiful.

For a spider.

Now you know.

A Beautiful and Devastating Fish

If I end up falling in love with the coral reef ecosystem, there’s a good chance I’ll get my heart broken. It is so beautiful, so delicate, so complex, so exquisitely balanced—and under assault from so many directions. There is overfishing, there is acidity from atmospheric carbon, there is sea temperature rise from global warming, there is sea level rise from global warming. Developers mow down the mangrove forests that protect them from sediment runoff and they get buried. Nitrate pollution from agricultural runoff and sewage causes algae growth that smothers them and takes all their oxygen. And even ecotourism ain’t helping.

And now, as if they needed another problem, there are lionfish in the Caribbean.

Lionfish (Pterois volitans) are spectacular creatures. They are beautiful, they are unusual, they are magnificently talented predators, armed with dramatic, arching, venomous spines—and they don’t belong in the Atlantic, they belong in the Pacific.

Mangrove forests protect the reef from sediment runoff
Photo courtesy of NOAA, public domain, via Wikimedia commons

Legend has it that lionfish got introduced into the Atlantic when Hurricane Andrew destroyed a public aquarium in Florida in 1992 and its six lionfish ended up in Biscayne Bay, but actually they had been sighted before then. We can’t know, but probably it was thoughtless people giving up their aquarium hobby and tossing them into the ocean. In the last decade, they have gathered their momentum, and their numbers and their range are both absolutely exploding. The alarm you hear when you read up on it is frightening. Environmentalists are scared. The National Oceanic and Atmospheric Administration (NOAA) is scared. Mark A. Hixton of Oregon State University says it “could very well become the most disastrous marine invasion in history.”

They eat juvenile fish, and they’re very good at it. And coral reefs are tremendously important nurseries for juvenile fish. A lionfish can eat from twenty to thirty small fishes in just a half an hour. A single lionfish can reduce the juvenile fish population in his area by 79% in just five weeks. And there is a one-word answer to the question of why this threatens the entire reef and not just the fish population, and that word is balance.

I thought I’d seen some delicately-balanced ecosystems before I started reading up on coral reefs. Man, I didn’t know what delicately-balanced was. I’ll be writing more about coral reefs without a doubt, but one of the many hair-raising balancing acts that goes on out there every day is between the coral and the algae. Algal encroachment is devastating to coral reefs, and the small fish are the herbivores who keep the algae grazed back.

In the Indo-Pacific oceans where lionfish come from, they have predators. Groupers and several other fish will take them out, but the groupers on this side of the world don’t seem to know how to do it, and besides, we’ve overfished our groupers pretty badly. Also, in their native waters, the prey fishes all know what a lionfish is, and they flee from it. Some scientists think that one problem is that lionfish are so bizarre that no one around here knows what they’re looking at. They look strange and they hunt strangely. They herd fish into a corner with those pectoral spines and then nail them with a lightning strike. They blow water across their prey to disorient it, they have specialized swim bladders that they use for side-to-side motion, and their stomachs can expand to thirty times their normal size, with the result that they can gulp down something two thirds their own length. They’re outlandish, and the fish around here have never seen anything like them. They don’t look like a predator to their prey, and they don’t look like prey to their predators, so they get to sashay around doing what they want and gobbling everything up. Some divers are actually trying to train fish like sharks how to eat a lionfish, by feeding lionfish to them, but it hasn’t been real effective so far, and anyway, there’s argument about it. A lot of folks make the reasonable point that it’s probably a bad idea to teach sharks to associate humans with food.

lionfish_at_Shaab_El_Erg_reef_(landscape_crop)

Outlandish: No one in the Atlantic knows what to make of a lionfish
By Alexander Vasenin CC BY-SA 3.0 via Wikimedia Commons

But if there’s a bit of good news to be gleaned, it’s this: lionfish are very tasty.

There is a campaign underway in the environmental and diving communities here in Akumal to get lionfish onto restaurant menus. There’s a small outdoor restaurant down the road from us that specializes in them, and the proprietress is an environmentalist, diver and lionfish hunter. Akumal recently held its first lionfish derby, in which the diver to spear the most lionfish wins a prize, and chefs are ranged up and down the beach handing out samples of lionfish dishes. Even NOAA has launched an Eat Lionfish campaign, and the folks at REEF.org have published a cookbook. The FDA played the party pooper and pointed out that you risk ciguatera poisoning, and does not recommend eating lionfish. Ciguatera poisoning is caused by a neurotoxin produced by a small dinoflagellate called Gambierdiscus toxicus which lives on the algae and coral of tropical reefs. It gets grazed by the herbivores and magnifies up the food chain, so the large, top-level predators are the ones to avoid. But other folks point out that it’s a risk you run when you eat any reef predator, including very common menu fish like grouper and snapper. Susan and I walked down the street and tried some lionfish. They’re delicious.

But, as you probably guessed, we’re stuck with lionfish now. Opinion is unanimous that we will never eradicate them completely. All we can do is try to keep their numbers pummeled down. That’s why species introduction can be such a horrific act, and it’s why I’m such a native species bigot. You can never un-introduce a species once it gets established. Evolution just builds its organisms way too well for that. The historical record is littered with environmental disasters caused by intentional or unintentional species introductions. Someday I might compile an anthology of the more spectacular ones and publish it here. For now, though, I think I’ll go for a swim and enjoy the haunting beauty of our reef—and then maybe walk over for a lionfish taco.

Now you know.

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The Baddest Act In the Jungle

Let’s just put it this way: Crocodiles are one of their prey species.

Jaguars are the baddest act in the jungle, and when there’s not an animal in your ecosystem who can take you down, it gives you personality issues. Picture it: You are the biggest cat in the Americas. You are the third biggest cat in the world. Those cougars and bobcats and lynxes in North America—they’re not even related to you. You’re in the genus Panthera, thank you very much. Your cousins are the lions of the African savanna and the tigers of Asia. When that ancestor of yours crossed the Bering land bridge to the Americas back in the Pleistocene era (along with a gifted ape called Homo sapiens), he was almost twice your size, and lived and fought in the megafauna world of mastodons and wooly mammoths, and God only knows what kind of predatory fights he got into, and actually the scientists don’t know either, but they generally call him “Panthera genus, species unknown”, which means that maybe 13,000 years later, he had become you: Panthera onca. Terror of the jungle. Apex predator in four different ecosystems. Deity of the Maya. The jaguar.

He’s in these forests. Let’s talk.

* * * *

Susan and I were lucky enough once to see a cougar (on a long night training run in Fort Ord), but it’s highly unlikely we’ll be fortunate enough to see a jaguar in our lifetimes. They are even more reclusive than the cougar, and they favor dense jungle. But you can hear them. Our friend Victoria hears them at night behind her house outside Tulum. They growl and roar, like lions, calling back and forth in the jungle. And we know a hiking guide near Puerto Vallarta who came around a bend in the trial once and found himself facing one. They stared at each other for most of a minute. He said it was the most focused his mind has ever been. Then the jaguar just turned and walked away.

But actually, in hindsight, our friend hadn’t been in any danger. Jaguars bring to mind that iconic line from the film The Godfather: If I wanted to kill you, you’d be dead. They’re ambush predators, not chase predators. They stay invisible to you until they are within a short charge or a single bound. You don’t even know you have a problem until he’s airborne. The rosettes on his coat are perfect for the dappled sunlight of deep forest, and even scientists who study big cats for a living say they’re remarkably skilled at this ambush-predator stuff.

jaguarPanthera_onca_at_the_Toronto_Zoo_2

A jaguar shows off the gape of his jaws
By MarcusObal [GFDL or CC BY-SA 3.0], via Wikimedia Commons

But once they hit a large animal, the way they close the deal is even more remarkable. They not only are the biggest cat in the Americas, they also have the biggest and most powerful jaws, even proportionally. Their bite carries two thousand pounds of force, more than any other cat, and the gape of their jaw is astonishing. So when they jump a large prey animal, they do something no other cat can: they drive their canines through the skull. Usually right between the ears. Death is instantaneous. Neck-wringing is for sissies.

It is thought that this technique evolved because eleven thousand years ago (give or take a couple) there was an event called the Pleistocene Extinctions, in which we lost thirty-three of our forty-five genera of large mammals (those gifted apes I mentioned probably had a hand in this). For a while there it got pretty hard to find a mammal, but there were lots of armored reptiles around, like turtles and crocodiles, and also giant armadillos—if you could get through their armor.

They do kill livestock, and they’re strong enough to carry a young cow up a tree. One was observed dragging an 800-pound bull twenty-five feet across a pasture. And when they kill a horse, what they will often do is leap on its back, put one great paw on the muzzle, one on the nape of the neck, and then twist, like an evil chiropractor, dislocating the neck.

They love water. They like to be around rivers, they can catch fish in a pinch, and crocodile is one of their favorite foods. They will kill a crocodile by exploding out of the water like a crocodile. They can swim carrying a very large kill. They are also completely at home in the trees, and they can hunt arboreally. They can even make a go of it in habitats like arid grassland and seasonally flooded wetlands, but by far they prefer deep jungle. It’s what they’re built for. They’re not long-limbed and fleet-footed like their cousins on the savanna. That doesn’t work in dense jungle. They’re huge, but they’re compact—short-limbed and extremely muscular.

They are considered a keystone species. A keystone species is one which has a disproportionate influence on the ecosystem. It’s a reference to the keystone at the top of a stone arch. It carries less weight than any other stone, but remove it and the arch collapses. The jaguar is the apex predator. Remove him, and you get an over-abundance of the next predator down, and then a cascading re-shaping of the whole food chain.

They used to be common in the United States. Thomas Jefferson recorded their presence in 1799, and they were seen in California (Monterey is mentioned), as far north as Missouri and as far east as the Carolinas. They quickly got exterminated by Anglo-Americans, and the ones in the Southwest were the last to go. The last female jaguar was shot by a hunter in Arizona in 1963. Arizona outlawed jaguar hunting in 1969, but with no females, there wasn’t much hope. Over the next twenty-five years only two male jaguars were seen (and shot). It seemed to be all over for the jaguar in the US.

Then, in 1993, an Arizona hunting guide named Warner Glenn was hunting in the Peloncillo Mountains when his dogs brought a large animal to bay on top of a rock. It was a jaguar. It changed his life. On the spot, he became a jaguar conservationist and researcher. He knew the mountains well, and he started planting webcams. The sightings started coming in. There were jaguars in the States again.

Glenn still hunts, but you don’t want to harm a jaguar around him, and don’t even get him started about that stupid border fence that fragments their habitat and blocks the migration of everything except human beings. Warner Glenn belongs to a bygone breed—a hunter-conservationist, in the mold of Teddy Roosevelt.

Jaguars adorn a temple in the Chichen Itza ruins, Yucatan Peninsula, Mexico
By Marco Soave [GFDL or CC BY-SA 3.0, via Wikimedia Commons

There is a jaguar god in every major Mesoamerican culture. Carvings of them are all over the Maya ruins, shamans are thought to be able to change form into a jaguar, and only the royalty were allowed to wear jaguar pelts. The Maya believed the jaguar was able to move between worlds, from physical to spiritual to the underworld. This is probably because the jaguar can operate in so many realms, from aquatic to terrestrial to arboreal, and also because he can be active in day or night, and to the Maya, day and night are two different worlds. The Olmecs, west of here, even had a supernatural character in their folklore that anthropologists call a were-jaguar, a shape-shifting, half-man, half-jaguar sort of guy, who was believed to be the product of sex between a woman and a jaguar. Maya kings would give themselves grandiose names incorporating the Maya word for jaguar (balam), so there were kings named Scroll Jaguar, Bird Jaguar, Moon Jaguar, and Jaguar Paw III.

The Maya created an instrument involving a drum, a string, a stick and a rasp, which sounds exactly like the growl of a jaguar (which is a frightening sound), and I mean they nailed it. If you were walking through the woods and you heard this thing, you’d pee your pants. This proved to me for the second time that the Maya had some serious acoustical skills. (Read this post for another example.) By the way, this might be the only stringed instrument that evolved in the Americas, but be careful who you say that to, because they’re still arguing. The problem with stringed instruments is that they don’t survive well, so it’s pretty hard to know. The reason we know about this one is that the Maya were a literate people, and carved all manner of text and images into their stone walls, including a bass-relief picture of a guy playing this thing. An Ethnomusicologist named John Burkhalter was able to build one, and you can hear him play it below. You can hear the real animal here.

Jaguar numbers are dropping precipitously. Their range has contracted at both the north and south ends, and they don’t handle habitat destruction and fragmentation well. But also there’s hunting. In the nineteen-sixties, 15,000 pelts per year were coming out of the Amazon Basin. Also, they do kill a lot of cattle. Someone did a study and the ranchers are not exaggerating this. Most Latin American ranchers shoot them on sight, and a large operation will even have a full-time jaguar hunter on the payroll.

Which is a sad way to end a story about a magnificent animal, but hell, those are the times we live in. I’m almost getting used to it.

Now you know.

Jellyfish and Formula One Race Cars

When you get stung by a jellyfish, you’ve just been harpooned by a projectile that was fired with an acceleration of 5.4 million G’s.

Admit it, you didn’t know that.

For years, jellyfish have been one of my favorite mind-blowing organisms, but two things in the last two days prodded me to finally write an article about them. One was our good friend Dave. Dave lives on the shore of a beautiful Caribbean lagoon in Mexico (and so do we—we rent a casita from him), and he has noticed that lately there are a lot more jellyfish than usual in the lagoon. He loves the lagoon and is always keeping an eye on it, and he is afraid something is amiss, so he asked me if I could look into it. Then one day later Susan got an email from another dear friend of ours, Cathleen, back in Monterey, who tells us that millions of small surface jellyfish called velellas had washed up on the beach there in the last few days.

So okay, it’s time to do this thing.

Jellyfish (phylum Cnidaria) are as remarkable for what they are not as for what they are. Listen to what your basic jellyfish does not have: He does not have a brain. He does not have a heart or a circulatory system. He does not have lungs or gills. He does not have eyes. He does not have a skeleton. And he might be a she, because he does have a gender.

He only has a single muscle around the perimeter of the bell. He only has a single orifice, called a mouth-anus, and a single gastro-intestinal organ behind it, which is stomach and intestine combined, and does all the digesting before he spits out the remains. The closest thing he has to a nervous system is called a neural net, which can be pictured as a non-centralized web of neurons sort of draped over the bell. When you poke him, each neuron fires to its neighbor, in an “I just felt something, pass it on!” sort of way, and somehow he ends up responding and pulsing away in the other direction.

In fact, even what he does have, he does not have very much of, because he is 98% water, and that’s a very cute trick—only two percent of him is anything he has to find or pay for. It’s a very cheap way to be an organism. The Jell-o in your refrigerator is 90% water, so jellyfish have the process dialed in a lot better than the Kraft Foods corporation does. As for us, we’re about 55 to 60 percent water, so we’re pretty high-maint. It takes a lot of nutrients and expensive chemicals to make a human being. (At today’s prices, you’re worth about $160.00.)

They’re able to pulse around, but that’s as much to draw prey into their tentacles (actually called oral arms) as anything else. The reason they don’t have to obsess too much about locomotion is that they’re planktonic. Most people don’t realize this, but you don’t have to be small to be plankton—it just means that you go where the currents do, and that’s what jellyfish do. In all, jellyfish seem to have been designed by an engineer who was over-obsessed with the cheap-and-simple design model, and they seem merely fun, just a weird and amusing creature—until you get to the sub-cellular level. That’s where jellyfish go from being amusing to being amazing.

So think about this for a moment: You’re ninety-eight percent water. Even a soft, pudgy human finger can poke right through you. You’ve got no speed, no hardened exterior, no teeth or claws—and what do you decide to go around killing and eating for a living? Bony fishes, fer God’s sake! How do you subdue something like a fish, which has a skeleton, scales, fins, spines, teeth, thrashing muscles and an intense desire not to be killed?

With toxins, that’s how. You poison them. And now I want to talk about dish gloves.

When you get stung by a jellyfish, you have been harpooned by thousands of tiny projectiles on the ends of flexible hollow tubes, fired from cells called nematocysts. The nematocysts cover the oral arms that hang down curtain-like from the bell, and the way those things fire is just amazing. Picture taking a dish glove, and poking one finger of it inside-out into the glove. Now put the opening of the glove over your mouth and blow into it. The finger everts—it shoots outward until it’s fully extended and right-side-out again. That’s how those nematocysts fire. What’s absolutely brilliant about that design is that there is no drag. None. This thing is not travelling through the water, it is growing through the water. Its surface is not moving at all relative to the water, so it can fire at tremendous speed, and without veering off due to turbulence. Sticking with the dish glove analogy for one more moment, if that thing were the diameter of a dish glove finger, it would be the length of a football field. And it fires all that distance through water, and in a straight line.

And with up to 5.4 million G’s of acceleration. They’re still studying it, but that seems to be the upper estimate. To give that number some meaning, you have to browse down a chart of sample G-force numbers, which is an extremely fun thing to do (okay, maybe I’m a little weird, but I call it a good time). When the Space Shuttle takes off it never gets above three G’s. The top recorded drag racer managed to hit 4.3. Aerobatic planes can deliver 4.5 to 7 G’s. Twenty-five G’s and up is a number that will usually kill you. Your average bullet fires at 100 to 200 G’s. It is thought that a guy named David Purley experienced the highest G load of any human being without dying. He was a Formula One race car driver. On one particularly bad day he went from 108 miles per hour to zero in twenty-six inches. He actually was a very courageous guy—he once abandoned his own race to try to save a driver trapped under a burning car. Later he went into aerobatic flying and died in a plane crash, but anyway, you don’t usually get into the thousands or millions of G’s until you’re talking about either sub-atomic particles in accelerators, or jellyfish.

: David Purley
Photo by Gillfoto CC BY-SA 3.0, via Wikimedia Commons

And would you like to know what force it is that instantly creates this tiny but incredible, millions-of-G’s explosion? Osmosis, that’s what.

This blew me away (so to speak). I had always thought of osmosis as a lazy, slow kind of a force that given time will equalize concentrations on opposite sides of a permeable membrane. Not so—apparently it can be both very powerful, and very instantaneous. The bulb or capsule (called a cnida) into which that dish glove finger is tucked is filled with a solution rich in suspended calcium, but it’s safely imprisoned behind waterproof walls. What happens when the trigger is pulled got a little technical for me and changed from article to article, but if I understand it correctly, a change in electrical polarity causes a membrane to instantly go from impermeable to permeable, and suddenly all that calcium-rich fluid is exposed to surrounding normal fluids, and the osmotic reaction is absolutely explosive. Water rushes into the bulb at lightning speed, briefly creating 140 atmospheres of pressure, and the nematocyst blows, in what one scientist calls “the most explosive envenomation process that is presently known to humans.”

The harpoon tip is also designed to rotate as it travels, like a bullet fired from a rifled barrel, and I’m assuming that that also helps to keep it straight. And, of course, the whole tube (and bulb) is full of venom. When it finally reaches its full length, which is usually after it’s thoroughly buried in your flesh, there is still pressure left in the bulb, so the harpoon tip blows off the end of it, and all that venom empties into your system. Cute, no?

: Nematocyst Firing Sequence
By Spaully [CC SA 1.0 or Public domain], via Wikimedia Commons

The trigger that gets pulled is interesting too. There are actually at least two. One is mechanical and simply gets depressed by the prey like the trigger on a gun (called a mechanoreceptor). But to keep these valuable nematocysts from firing on wharf pilings and other objects that cannot be eaten, there is also a chemosensor—basically an olfactory—which has to detect something organic like animal protein before the system will arm itself. There are some species of box jellyfish (class Cubozoa) in Australian waters that are among the most venomous creatures in the world and can kill you outright, and have enough venom on board to kill sixty others like you, but the only thing you need to protect yourself from them is pantyhose. That’s what the Aussie lifeguards used to wear before there was such a thing as a Lycra bodysuit. The nematocysts are plenty long enough to fire through the fabric, but the chemosensor is a tiny thing and cannot reach through the fabric to detect skin, so nothing fires.

* * * *

Well, I could keep going, believe me there’s more, but I should wrap up, and circle back around to what Cathleen and Dave have each been seeing.

Cathleen, those deep blue little surface jellyfish you’ve been seeing washed up in the millions on the beaches of Monterey are commonly called by-the-wind sailors, and their latin name is Velella velella, the only species of their genus. They are cnidarians, but they’re pretty different from the typical jelly I’ve been describing here. They’re more related to the Portugese man-of-war, and, like the man-of-war, they’re colonial—there’s more than one cnidarian at work there. They’re an interesting animal. They live entirely on the surface, floating on gas-filled chambers like a Zodiac raft, and with little transparent, leaf-shaped sails sticking up. The velellas are longer than they are wide, and their sail sticks straight up, but it is mounted diagonally, set at forty degrees off the longitudinal axis of the creature. This allows them to sail in a direction up to sixty-three degrees off the downwind direction, which is a level of control that pushes the limits of what we call planktonic. Wind is usually light at this time of year, but when there is a weather anomaly and the wind gets stronger, millions of them will strand on beaches up and down North America (these things exist in all the world’s waters, and from sub-arctic to tropical latitudes). Here’s the fun part: When that happens, as it is now, and you’re looking at foot-thick windrows of decomposing velellas on the beach, you would think this has been an absolute disaster for the poor species, but there’s a catch. Velellas have an isomorphic form, and half of them have sails that are angled forty degrees the other way. I kid you not. That half of the velella population is still out at sea right now having a good time.

: Velella, aka By-the-wind Sailor
By Wilson44691 [CC0], via Wikimedia Commons

Dave, the question you ask is more complicated, and you, like Cathleen, are also looking at a delightfully non-typical jellyfish. It is commonly called the upside-down jellyfish, or the mangrove jellyfish, but there are several species, so yesterday I took a dive and looked at one of them myself, and if I’ve ID’d it correctly it’s Cassiopea andromeda (there must have been an astronomer in the room with the taxonomists). I remember there being a tank of these in an exhibit when I was a docent at the Monterey Bay Aquarium, and looking at them, lying there on the tank bottom, upside-down on their bells and pulsing with their oral arms waving in the water, and wondering, “Where in the hell did they find those things?” Now they’re 200 feet from where I’m sitting. They can pulse around like any other jellyfish, but then they’ll turn upside-down and settle on the floor of a shallow lagoon with their oral arms sticking up, looking for all the world like a sea anemone, which is also a cnidarian, just built upside-down. (In fact, sometimes a sea anemone is a jellyfish, just in a different life stage, but that will have to wait for another article.)

They lie there like that because they are photosynthesizing. They’ve taken a cue from the coral around them, and just like the coral they have a symbiotic relationship with a photosynthesizing algae called zooxanthellae, and it does most of the nourishing for the creature, though the jellyfish still kills and eats small plankton and other prey.

To get to your question, several things can cause a surge in jellyfish numbers, which is commonly referred to as a jellyfish bloom. One is runoff. Nitrates and other pollutants and nutrients, like sewage or agricultural runoff, cause something called eutrophication, in which the unusual flood of nutrients causes an intense algae bloom and the algae suck up all the oxygen, creating oxygen-poor “dead zones,” and jellyfish are much better able to handle low oxygen than the bony fishes with whom they compete for a lot of their food. Jellyfish are more able to handle acidity in the ocean waters than other organisms (though no one is sure why). Coastal and off-shore construction of things like pilings and drilling platforms create more attaching surfaces for jellyfish in their polyp, or anemone-like, stage. Jellyfish reproduction is accelerated by warmer waters. And because of the competition for prey between jellyfish and bony fish, pretty much anything bad you do to your fish populations will create more jellyfish. Jellyfish also have a multi-stage reproductive cycle that includes some non-sexual cloning, so they have a fallback process that allows them to continue to reproduce while they wait for their numbers to rebound enough to find mates. To understand the broad strokes of what’s going on, remember how simple jellyfish have kept themselves. Animals like bony fishes, with high metabolisms, complex organs, and high oxygen and energy demands, simply find it hard to compete with jellyfish when things change, or times get tough. In other words, when human beings start screwing with the planet.

There is huge argument right now about jellyfish blooms. Some see an extremely scary global trend. There is a jellyfish in the waters between Japan and China that measures six and seven feet across the bell and weighs 480 pounds, and its blooms have become annual. One fishing trawler capsized itself trying to haul in its nets, and the crew had to be rescued. People are blaming pollution from the Yellow River in China. Last year, nuclear power plants in Scotland, Japan, Israel and Florida had to shut down due to jellyfish clogging the inlet pipes of the cooling system. Ireland’s entire salmon farming industry got destroyed one year by jellyfish. Desalination plants have also had to shut down.

But the problem is, all this shouting and arm-waving is anecdotal. Booms and busts in nature happen all the time, and we actually know very little about jellyfish. Jellyfish are notoriously hard to study. You can’t tag one. They blow into town and then blow out and nobody knows where they go. Haul one onboard and you have a pile of slime. Put them in any ordinary fish tank and they all end up piled in one corner, or sucked up against the filter inlet. We don’t know jack scat (that’s a euphemism I just made up) about jellyfish, and we need to. People have been quick to implicate global warming, but Steven Haddock of the Monterey Bay Aquarium Reseach Institute believes that there are many other possible causes that would come before that. “It sounds to me like scary rhetoric to try to get funding,” he says. Rob Condon of Dauphin Island Sea Lab in Alabama has been gathering data going back to the 1700’s, and believes that there is nothing suggesting a global catastrophe. He points out that four thousand years ago in Crete, they were painting pictures on their pottery about jellyfish blooms.

So, like so many things I write about, we don’t really know. And we need to. But what haunts me about the overarching trajectory of this story is a fairly simple truth that is apparent to me no matter which papers I read or which way I turn them, and it goes something like this: Anything bad we do to our fish populations, or our oceans in general, is likely to create jellyfish blooms.

I don’t have a good feeling about this.

Now you–

Well, no, I guess you don’t.

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Anti-grav Geckos

“That’s really a pretty cute trick,” I said to myself.

What sort of surprised me was that I was saying anything to anyone at all, including myself. Susan and I had just watched a World Cup soccer match in a thatched palapa bar here in Akumal, Mexico, then walked a mile and a half home, and if the heat was an unprovoked assault, the humidity was a crime against humanity. With three margaritas in me and drenched in sweat, I burst into the bedroom and groped for the air conditioner like a poisoned man groping for the antidote, and then we both fell backwards onto the bed—and then this little gecko ran across the ceiling above my face.

: The gecko above our ceiling fan (Sorry, not the greatest shot)
Photo by Randy Fry

Between the gecko and my face whirled the scythe-like blades of a ceiling fan, in a sinister blur. Losing her grip would have been a scene from a grade-B gecko gore movie, but she was nonchalantly confident, and scampered upside-down all the way across the painted concrete ceiling to the wall, then transitioned fluidly to the vertical surface, and disappeared into her hidey hole behind the valance of the window blind. Okay, I said, still managing somehow to converse with myself. I have to find out how they do that.

Just as soon as the temperature in here drops by twenty degrees.

Like most times I’ve ended up reading something astonishing, the reason I wanted to know more was that I already knew a little. I knew that they do not do this with claws, they do not do it with suction cups, they do not do it with a goopy adhesive substance, and they are not affected by the smoothness or roughness of the surface. What the hey? I started reading.

: A better shot of a house gecko
By Praveenp
[CC BY-SA 3.0], via Wikimedia Commons

If we’ve ID’d her correctly, she’s commonly called the house gecko (Hemidactylus frenatus), and I call her a she because she barks at night. I kid you not. It took us forever to figure out what that sound was. It’s a female house gecko advertising for a mate. But something Susan found out in her research is that she doesn’t need a mate. The house gecko doesn’t, I mean. The house gecko is parthenogenic, meaning that the female is capable of making babies without the help of a male. That’s also a very cute trick, but actually she only does it in a pinch, because when you do that, genetic diversity suffers. In case you don’t remember your high school Darwinian evolution, or in case they’re not teaching it anymore, sex is all about diversity. Diversity is the only reason you have a sex life. You don’t want all your kids to be carbon copies of yourself, because if your environment throws you a curve ball, you want some of your kids to be weirdos, because there’s a chance the weirdo might be able to handle the change. Which is probably the only reason I’m on the planet.

Everyone around here loves having a gecko in their house, and we are blessed with either a couple of them, or with one who is very mobile, I haven’t figured out which yet. The reason people love them is that they eat bugs, and the bugs down here in the tropics are, well, let’s just say the potential subject of several future Ranger Randy articles. In Spanish, house geckos are called limpia casas—house cleaners. They can eat a spider twice the size of their head, and I just love that about them. For Susan’s part, she loves that they eat mosquitos.

They’re pretty small lizards. They only get about as long as your finger, but they leave huge droppings, and Susan and I thought we had rats in the house, which are not a part of the natural wonderland we wanted to invite into our living space. The property caretaker, Rene, had to convince us that they were gecko droppings.

Even this fascinated me. Like any self-respecting naturalist, I like turds. Okay, the field of study is actually called scatology, but I don’t mince words for my readers—we naturalists like turds. There is a lot of information in their contents, and there is a lot of information in their abundance, location and distribution, and the really cool thing about them is that they don’t run, they don’t hide, and they don’t bite. Turds are great sources of information, and there’s not a wildlife biologist anywhere who is at all shy about working with them. And actually, I had already noticed that these had one white end, which means that you’re dealing with an animal who does not urinate. The white is uric acid. That usually means a bird or a reptile. So I was easily convinced that we had geckos and not rats. (But good heavens, the size of those things! Ow!)

* * * *

So now I’m remembering my father in one of our late-night debates (and we had a lot of them) and he’s saying, “We must remember that nature is not divided into disciplines the way universities are.” It was one of his favorite quotes, and what’s annoying me as I write this is that I can’t remember which famous scientist he attributed it to, and now, even with all the power of the Internet at my fingertips, I can’t for the life of me find it, so if anyone out there can source that quote, please email me, because I’m dying to remember. Maybe an attribution doesn’t exist and it’s one of those quotes that came from no one in particular. It doesn’t matter, they are profoundly wise words, and sure enough, when I looked into this anti-grav thing that geckos do, the biology of it took me straight into physics.

There is a very faint and feeble force in physics called the van der Waals force, and even if you are a scientist, it might not be a force you hear very much about. It does hold molecules together, sort of, but it is not to be confused with the irrevocable force of a chemical bond, which results from something slam-clank solid like an electron shared between two positively charged nuclei, and is bomb-proof and almost impossible to break. No, the van der Waals force is a ghost of a force compared to that. I’m not really qualified to explain it to you, but it has to do with the charge fluctuations of molecules naturally falling into sync and creating a tiny attraction. It is incredibly subtle, but it is the reason that if you get any two molecules in this universe close enough to each other, they will be slightly attracted to each other. It is weak and easily disrupted and easily overpowered, but it is there, and if it were not there, you would not recognize this place. Without the van der Waals force, water vapor would not condense into either liquid or ice. Without it, there would be no crystalline structures—no snowflakes, no quartz. It is the reason water has surface tension, and without it there would be no such thing as a droplet. It is the reason we have melting points and boiling points, and it makes possible gigantic molecules like enzymes, and DNA. Without the van der Waals force, life as we know it would not be possible, and it is the reason geckos stick to the ceiling.

We don’t feel the van der Waals force when we touch a wall because on the microscopic level so little of our body is actually in contact with it. There is the shape of our hand, the roughness of our skin, the way the two shapes do not conform to each other. Down there on the molecular level, very, very few person molecules are actually touching wall molecules. That’s the problem the geckos solved. So I’m going to take you on a zoom-in, a big one. Hang onto you chair…

First of all, let’s zoom in on the bottoms of those cute little club-shaped toes that geckos have. The bottoms of those toes are plated like the treads of a caterpillar tractor so that they can roll on and off of a surface incrementally and fluidly. More on that in a bit.

: A gecko shows off her laminellae (Click to enlarge)
By ZooFari [CC BY-SA 3.0], via Wikimedia Commons

Zooming in on one of those plates (called laminellae), we find that it is covered with tiny hairs, and each hair is pretty short, but there are a ton of them—up to 1,400 per square millimeter. Let’s zoom in more:

On the end of each single hair (called a settae) there are, I kid you not, up to 1,000 little pads called spatulae, and each one is only 200 nanometers wide. Now, to give you an idea of where we are at this point in our zoom, a nanometer (nm) is a billionth of a meter. So these structures with which our little gecko finally makes physical contact with the painted concrete of my ceiling are actually smaller than the wavelength of visible light.

The end result? There is no part of any surface this gecko walks on that gets missed by this set-up. She has maximized her surface area to an incredible extent. She is playing touchy-feely with our ceiling at almost the molecular level. That feeble little van der Waals force has become a rock-solid bond. She has no fear. She will never fall.

In fact, it works so well that she actually has adhesion to spare. Evolution did have to over-build her a little bit. After all, she lives a fairly complicated life, and as she moves around, not all those little structures are in contact with the wall all the time—in fact, not even all four of her feet are on the wall all the time. So at any given moment, she’s only using a fraction of her adhesion capability. But scientists love to run theoretical numbers. They estimate that if you could set up an ideal situation and get every spatulae she owns on the ceiling at the same time, you could hang 293 pounds from that little lizard.

Which left her—or at any rate her ancestors—with an interesting problem that had to be solved as this thing evolved. If you took your average appendage—say a human hand—and covered it with those spatulae and setae and slapped it on the wall, you’d never get it off. You’d still be tugging at it. And that’s why geckos’ feet have that unusual anatomy I mentioned. Everything happens on those little tractor-tread plates, and her toes are double jointed—that is, the knuckles can bend backwards (it’s actually called digital hyperextension), so she is able to roll her toes off the wall.

When this van der Waal angle started to become apparent to researchers (only a decade or so ago), technology began to imitate nature. A team at Simon Fraser University in British Columbia has built a robot inspired by the gecko. Sure enough, it’s on tractor treads. They have managed to create artificial setae out of a material called PDMS whose real name I don’t have room to type here, and this thing can climb walls wet or dry, smooth or rough. They’ve already got the prototype working. You can watch it below:

A team at Northwestern University in Evanston, Illinois is creating a tape called Geckel, which will work wet or dry, smooth or rough, and won’t wear out for a thousand or more uses. They’re picturing medical applications for it, like a replacement for sutures which is impervious, just like sutures are, to water and other conditions.

All of which is very cool, but before I shell out for one of those robots, they’re going to have to teach it how to eat spiders.

Now you know.

Iguana iguana

It sucks to be an iguana. That’s why they have that look on their faces. If you’re an iguana, everyone just wants to eat you. You’re a gentle vegetarian who wouldn’t harm a fly, but all it buys you is a job as the main protein source for an entire food chain. If you’re an iguana, you’re a talented survivor in three different ecosystems—you’re a terrestrial animal who can become aquatic in a pinch or become arboreal in a different pinch, but it doesn’t do you any good because you’ve got predators in all three places. Even human beings have been eating iguanas and their eggs for over seven thousand years, and call them gallina de palo, chicken of the tree. And now they’re being captured live and imprisoned in peoples’ terrariums. Iguanas don’t get any respect.

And they’re all around us here in Akumal, Mexico, where Susan and I now live, so I thought it was as good a place as any to start transitioning my Ranger Randy articles to the tropical biome. I looked into these large and handsome reptiles.

The green iguana (Iguana iguana, a name worth repeating) is a tremendously successful animal throughout south and central America, and they’re seldom green. Susan and I photographed the one above in Costa Rica. He’d clearly had a close brush—Susan calls him “Not the fastest iguana in the forest.” He’s a male, and the orange tone is breeding coloration. He’s maybe three feet long, but if they live long enough (which only a few do) they can reach five or six feet, and at that point they are well-armored and formidable lizards capable of defending themselves. They have claws, razor-sharp teeth and a dorsal crest of wicked spines that runs all the way down their back, and people who know have told me that you don’t want to get lashed by that tail. Even so, there are predators in these forests who can easily take them down. Just the line-up of cats in American tropical forests can give you the shivers, ranging from the tiny jaguarundi up through the ocelots to the huge and magnificent jaguar. It’s a fearsome place to call home, and it has made the iguanas tough, and good at what they do.

: Jaguar (Panthera onca)
By USFWS
[Public domain], via Wikimedia Commons

They like to hang out in trees for safety, and to soak up rays (thermal-regulate), and for a little extra margin, they like for the trees to be over water. If you run a river in Central America you can always see them lounging around way up there above your head. They do this so that if they are attacked from the air, they can take a dramatic, flying leap, plunging thirty, forty or fifty feet down into the water to hopefully escape. One nature guide we talked with had seen an iguana do this to escape a harpy eagle, and he hit the water only to be pursued to the far bank by a crocodile. They’ll even take a leap like that with no water around, and can survive a fifty-foot fall to the forest floor, braking themselves by shredding passing foliage with their hind claws as they plummet.

They breed like rabbits, and that’s because they actually occupy a similar ecological niche, being a primary herbivore at the base of the food pyramid. A female will lay up to sixty-five eggs in a burrow, and she doesn’t go in for parental nurturing. She lays the eggs and leaves, and that’s the end of that. The young fend for themselves right out of the eggshell, but they help each other through, staying in a family group for the first year, using the more-eyes-is-better philosophy, or, as scientists call it, the “selfish herd” behavior.

Their range is growing, and not for good reasons. It’s not clear if they were always as far north as Mexico, and they can be considered invasives here depending on who you talk to. But for sure they never belonged in Texas, south Florida or the Hawaiian islands. Puerto Rico wants to eradicate theirs. They have been introduced in all those places as stowaways on produce ships, or as escaped or released pets. They’re darlings of the pet trade right now. Everyone thinks they’re cool, but they’re actually very difficult to care for, and most of them perish within the first year, or—an even worse crime—get released into the wild by their owners, all of which is just one more reason (as if we needed one) not to go around caging wild animals. In 1995, though, an interesting thing happened. They suddenly colonized the Caribbean island of Anguilla, where they had never been before, and a scientist named Ellen Cinsky was able to figure out, with some significant biological and oceanographic investigation, that a raft of trees uprooted by a hurricane and containing a clutch of iguanas had drifted two hundred miles from another island over a period of three weeks, proving that it is not always human beings who mess up ecosystems by introducing species.

They have a “third eye” on the top of their head called a parietal eye, which is a very primitive form of light receptor also found in some amphibians and fishes. It is not capable of forming images but can detect something like the passing shadow of a raptor, and also guides their thermal-regulation. But their thermal-regulation only goes so far. At the end of the day these creatures are cold-blooded (ectothermic) and anything below about seventy-nine degrees farenheit puts them in a stupor, which is what led to the 2008 frozen iguana showers in south Florida. Bear with me. A rare cold front passed through, and the iguanas in the trees became insensible and lost their grip, and were falling out of the sky all over the place. The sidewalks and bike trails were littered with them. Later in the day when it warmed up most of them were able to stumble off and resume their lives.

Now you know.

About Randy Fry

A Bad Day on the Yucatan

Finding the Monarchs

When Squids Fly

**Caribbean Reef Squid (Sepioteuthis sepioidea)** Photo by Nhobgood Nick Hobgood CC BY

Two Caribbean Reef Squids (in different moods)
Photo by Clark Anderson CC BY-SA 2.5

Absurd Beaks and Materials Engineers

**Keel billed toucan (Ramphastos sulfuratus) on a neighbor’s property.**
Photo by Jim Fossheim.

**Hooded Oriole (Icterus cucullatus)**
By U.S. Fish and Wildlife Service Headquarters
[CC BY 2.0], via Wikimedia Commons

Gregarious, social and playful: A family of keel-billed toucans traverse the canopy.
Photo by Jim Fossheim

A Well-Defended Tree

A Beautiful and Devastating Fish

The Baddest Act In the Jungle

A jaguar shows off the gape of his jaws
By MarcusObal [GFDL or CC BY-SA 3.0], via Wikimedia Commons

Jaguars adorn a temple in the Chichen Itza ruins, Yucatan Peninsula, Mexico
By Marco Soave [GFDL or CC BY-SA 3.0, via Wikimedia Commons

Jellyfish and Formula One Race Cars

Anti-grav Geckos

Iguana iguana

About Randy Fry

The Cretacious-Tertiary (KT) Boundary Layer Photo by Mike Beauregard CC BY 2.0

Luis and Walter Alvarez at the KT Boundary Photo courtesy of Lawrence Berkeley Laboratory, public domain

Mabel Alvarez See page for author [Public domain], via Wikimedia Commons

Chicxulub Crater Gravity Map The white dots are cenotes created by the impact. The white line is the coastline. By Milan Studio.Milan studio at en.wikipedia. [Public domain], from Wikimedia Commons

The Chicxulub Crater By Yucatan_chix_crater.jpg: NASA/JPL-Caltech, modified by David Fuchs at en.wikipedia derivative work: Mircalla22 (Yucatan_chix_crater.jpg) [Public domain], via Wikimedia Commons

Monarch Butterfly (Danaus plexippus) Thomas Bresson CC 2.0, via Wikimedia Commons

Tagged Monarch Photo by Derek Ramsey [GFDL 1.2], via Wikimedia Commons

Monarchs Overwintering in Pacific Grove (a tagged individual is visible in upper center) Photo by Agunther (Own work) CC 3.0, via Wikimedia Commons

Monarch Butterfly Biosphere Reserve By Luis Avalos (Own work) [CC BY-SA 3.0], via Wikimedia Commons

Monarchs at the Monarch Butterfly Biosphere Reserve in Michoacan, MexicoBy Bfpage at en.wikipedia [Public domain], from Wikimedia Commons

Monarch CaterpillarPhoto by Linda Tanner, [CC BY 2.0], via Wikimedia Commons

Caribbean Reef Squid (Sepioteuthis sepioidea) Photo by Nhobgood Nick Hobgood CC BY

Two Caribbean Reef Squids (in different moods) Photo by Clark Anderson CC BY-SA 2.5

Keel billed toucan (Ramphastos sulfuratus) on a neighbor’s property. Photo by Jim Fossheim.

Hooded Oriole (Icterus cucullatus)By U.S. Fish and Wildlife Service Headquarters [CC BY 2.0], via Wikimedia Commons

Gregarious, social and playful: A family of keel-billed toucans traverse the canopy. Photo by Jim Fossheim

Ants patrol Dave and Nancy’s acacia. The beltian bodies are visible on the leaf tips.Photo by Randy Fry

My truck tire impaled by an acacia thornPhoto by Randy Fry

It is probably the ants who are keeping this area clear of weedsPhoto by Randy Fry

A wasp nest in an acacia at the Coba ruinsPhoto by Susan Fry

Bagheera kiplingiPhoto by Randy Fry

Pretty, for a spider: A male peacock spider (Maratus volans) does a courtship displayBy KDS444 [CC BY-SA 3.0], via Wikimedia Commons

Mangrove forests protect the reef from sediment runoff Photo courtesy of NOAA, public domain, via Wikimedia commons

Outlandish: No one in the Atlantic knows what to make of a lionfish By Alexander Vasenin CC BY-SA 3.0 via Wikimedia Commons

A jaguar shows off the gape of his jaws By MarcusObal [GFDL or CC BY-SA 3.0], via Wikimedia Commons

Jaguars adorn a temple in the Chichen Itza ruins, Yucatan Peninsula, Mexico By Marco Soave [GFDL or CC BY-SA 3.0, via Wikimedia Commons

Yal Ku Lagoon (the marine mammal is the author) Photo © by Susan Fry

David Purley Photo by Gillfoto CC BY-SA 3.0, via Wikimedia Commons

Nematocyst Firing Sequence By Spaully [CC SA 1.0 or Public domain], via Wikimedia Commons

Velella, aka By-the-wind Sailor By Wilson44691 [CC0], via Wikimedia Commons

Upside-down Jellyfish (Cassiopea andromeda)Photo © Raimond Spekking, CC BY-SA 4.0 (via Wikimedia Commons)

The gecko above our ceiling fan (Sorry, not the greatest shot) Photo by Randy Fry

A better shot of a house gecko By Praveenp [CC BY-SA 3.0], via Wikimedia Commons

A gecko shows off her laminellae (Click to enlarge) By ZooFari [CC BY-SA 3.0], via Wikimedia Commons

Jaguar (Panthera onca) By USFWS [Public domain], via Wikimedia Commons

Mabel Alvarez
See page for author [Public domain], via Wikimedia Commons

Chicxulub Crater Gravity Map
The white dots are cenotes created by the impact. The white line is the coastline.
By Milan Studio.Milan studio at en.wikipedia. [Public domain], from Wikimedia Commons

The Chicxulub Crater
By Yucatan_chix_crater.jpg: NASA/JPL-Caltech, modified by David Fuchs at en.wikipedia derivative work: Mircalla22 (Yucatan_chix_crater.jpg) [Public domain], via Wikimedia Commons

**Monarch Butterfly (Danaus plexippus)**
Thomas Bresson CC 2.0, via Wikimedia Commons

Tagged Monarch
Photo by Derek Ramsey
[GFDL 1.2], via Wikimedia Commons

Monarchs Overwintering in Pacific Grove (a tagged individual is visible in upper center)
Photo by Agunther (Own work) CC 3.0, via Wikimedia Commons

Monarch Butterfly Biosphere Reserve
By Luis Avalos (Own work) [CC BY-SA 3.0], via Wikimedia Commons

Monarchs at the Monarch Butterfly Biosphere Reserve in Michoacan, Mexico
By Bfpage at en.wikipedia [Public domain], from Wikimedia Commons

Monarch Caterpillar
Photo by Linda Tanner, [CC BY 2.0], via Wikimedia Commons

**Caribbean Reef Squid (Sepioteuthis sepioidea)** Photo by Nhobgood Nick Hobgood CC BY

Two Caribbean Reef Squids (in different moods)
Photo by Clark Anderson CC BY-SA 2.5

**Keel billed toucan (Ramphastos sulfuratus) on a neighbor’s property.**
Photo by Jim Fossheim.

**Hooded Oriole (Icterus cucullatus)**
By U.S. Fish and Wildlife Service Headquarters
[CC BY 2.0], via Wikimedia Commons

Gregarious, social and playful: A family of keel-billed toucans traverse the canopy.
Photo by Jim Fossheim

Ants patrol Dave and Nancy’s acacia. The beltian bodies are visible on the leaf tips.
Photo by Randy Fry

My truck tire impaled by an acacia thorn
Photo by Randy Fry

It is probably the ants who are keeping this area clear of weeds
Photo by Randy Fry

A wasp nest in an acacia at the Coba ruins
Photo by Susan Fry

Bagheera kiplingi
Photo by Randy Fry

**Pretty, for a spider: A male peacock spider (Maratus volans) does a courtship display**
By KDS444
[CC BY-SA 3.0], via Wikimedia Commons

Mangrove forests protect the reef from sediment runoff
Photo courtesy of NOAA, public domain, via Wikimedia commons

Outlandish: No one in the Atlantic knows what to make of a lionfish
By Alexander Vasenin CC BY-SA 3.0 via Wikimedia Commons

A jaguar shows off the gape of his jaws
By MarcusObal [GFDL or CC BY-SA 3.0], via Wikimedia Commons

Jaguars adorn a temple in the Chichen Itza ruins, Yucatan Peninsula, Mexico
By Marco Soave [GFDL or CC BY-SA 3.0, via Wikimedia Commons

Yal Ku Lagoon (the marine mammal is the author)
Photo © by Susan Fry

David Purley
Photo by Gillfoto CC BY-SA 3.0, via Wikimedia Commons

Nematocyst Firing Sequence
By Spaully [CC SA 1.0 or Public domain], via Wikimedia Commons

Velella, aka By-the-wind Sailor
By Wilson44691 [CC0], via Wikimedia Commons

**Upside-down Jellyfish (Cassiopea andromeda)**
Photo © Raimond Spekking, CC BY-SA 4.0 (via Wikimedia Commons)

The gecko above our ceiling fan (Sorry, not the greatest shot)
Photo by Randy Fry

A better shot of a house gecko
By Praveenp
[CC BY-SA 3.0], via Wikimedia Commons

A gecko shows off her laminellae (Click to enlarge)
By ZooFari [CC BY-SA 3.0], via Wikimedia Commons

**Jaguar (Panthera onca)**
By USFWS
[Public domain], via Wikimedia Commons