Flocking together

One of the most mesmerizing sights in nature is the collective motion of large groups of animals.

I remember watching films by Jacques Cousteau as a kid, and being fascinated by his underwater footage of schools of fish swimming along and then turning as one, the light flickering from their silvery sides as if they were each reflective scales on a giant single organism.  Murmurations of starlings barely even look real; the flocks swirl and flow like some kind of weird, airborne fluid.  But the most astonishing example of collective motion I've ever seen was when Carol and I visited Bosque del Apache Wildlife Refuge, in central New Mexico, a few years ago, during the migration of snow geese through the region.

"Get there early," we were told.  "At least a half-hour before sunrise.  You'll be glad you did."

We arrived just as the light was growing in the eastern sky.  The wetland was full of tens of thousands of snow geese, all moving around in a relaxed sort of fashion, calling softly to each other.  The brightness in the sky grew, and then -- without any warning at all...

... BOOM.

They all exploded into the air, seemingly simultaneously.  We have wondered many times since what the signal was; there was nothing we could discern, no handful of birds that launched first, no change in the vocalizations that a human would interpret as, "Now!"  One moment everything was calm; the next, the air was a hurricane of flapping wings.  They whirled around, circling higher and higher, and within ten minutes they were all gone, coursing through the sky toward their next destination.

[Image licensed under the Creative Commons CrunchySkies, Snow goose migration at Squaw Creek National Wildlife Refuge, Feb 2013, 25, CC BY-SA 3.0]

How animals manage such feats, moving as a unit without colliding or leaving members behind -- and seemingly without any central coordination -- has long fascinated zoologists.  Way back in 1987, computer simulation expert Craig Reynolds showed (using software called "Boids") that with only a handful of simple rules -- stay within so many wing-lengths of your nearest neighbors but not close enough to touch, match the speed of your neighbors within ten percent either way, steer toward the average heading of your nearest neighbors, give other members a chance to be in any given position in the group -- he was able to create simulated flocking behavior that looked absolutely convincing.  

Last week, a paper out of the Max Planck Gesellschaft showed there's another factor that's important in modeling collective motion, and this has to do with the fact that flying or swimming animals have a rhythm.  Look, for example, at a single fish swimming in an aquarium; its motion forward isn't like a car moving at a steady speed down a highway, but an oscillating swim-glide-swim-glide, giving it a pattern a little like a Slinky moving down a staircase.

Biologist Guy Amichay, who led the research, found that this gives schools of fish a pulse; he compares it to the way we alternate moving our legs while walking.  "Fish are coordinating the timing of their movements with that of their neighbor, and vice versa," Amichay said.  "This two-way rhythmic coupling is an important, but overlooked, force that binds animals in motion.  There's more rhythm to animal movement than you might expect.  In the real world most fish don't swim at fixed speeds, they oscillate."

The key in simulating this behavior is that unlike the factors that Reynolds identified, getting the oscillating movement right depends on neighboring fish doing the opposite of what their nearest neighbors are doing.  The swim-glide pattern in one fish triggers a glide-swim pattern in its friends; put another way, each swim pulse creates a delay in the swim pulse of the school members around it.  

"It's fascinating to see that reciprocity is driving this turn-taking behavior in swimming fish, because it's not always the case in biological oscillators," said study co-author Máté Nagy.  "Fireflies, for example, will synchronize even in one-way interactions.  But for humans, reciprocity comes into play in almost anything we do in pairs, be it dance, or sport, or conversation,"

"We used to think that in a busy group, a fish could be influenced by any other member that it can see," said co-author Iain Couzin. "Now, we see that the most salient bonds could be between partners that choose to rhythmically synchronize."

So zoologists have taken another step toward comprehending one of the most fascinating phenomena in nature; the ability of animals to move together.  Something to think about next time you see a school of fish or a flock of birds in flight.  Getting it right requires rapid and sophisticated coordination we are only now beginning to understand.

****************************************

Fishmobile

I know Life Follows Art, and all, but somehow I didn't expect the Art to be a sketch from Monty Python.

If you're a Python fan, you might remember a bit between Michael Palin and John Cleese, where Cleese plays a guy in the office that issues pet ownership licenses, and Palin is a guy who wants to get a license for his pet fish, Eric.

After being told that there are no licenses for pet fish, the following conversation takes place.

Cleese: You are a loony. 

Palin:  Look, it's a bleedin' pet, isn't it?  I've got a license for me dog, Eric.  I have a license for me cat, Eric. 

Cleese:  You don't need a license for your cat. 

Palin:  I bleedin' well do, and I've got one!  Can't be caught out, there. 

Cleese:  There's no such thing as a bloody cat license. 

Palin:  (places a piece of paper on the counter)  What's that, then? 

Cleese:  This is a dog license with the word "dog" crossed out and "cat" written in in crayon. 

Palin:  Man didn't have the right form.

Well, it turns out that they got the kind of license wrong, is all.  You don't need a license to own a fish, but the fish itself might need a license to drive a car.

In a paper that you'll think I'm making up, but I'm not, four researchers at the Ben-Gurion University of the Negev (Israel) have created a little car for a goldfish -- that is driven by the fish.

Dubbed the "Fish-Operated Vehicle" (FOV), it's a small plastic aquarium on four wheels, with a steering mechanism controlled by the orientation and fin-movement rate of the fish.  They then attached a food pellet dispensing device, so that the fish got fed whenever it moved its little car toward a pink stripe on the wall.

The authors write:

[The fish] were able to operate the vehicle, explore the new environment, and reach the target regardless of the starting point, all while avoiding dead-ends and correcting location inaccuracies.  These results demonstrate how a fish was able to transfer its space representation and navigation skills to a wholly different terrestrial environment, thus supporting the hypothesis that the former possess a universal quality that is species-independent.

Which is cool, and all, but it does make me wonder: how did they even think of doing this?  You know, this is the reason I'd never have made it in research science.  This isn't Thinking Outside the Box, this is Thinking in a place where the Box wouldn't even be visible through a powerful telescope.  I can't imagine in a million years being a behavioral scientist, and thinking, "Hey, I know!  Let's teach a fish how to drive a car!"

In any case, it's kind of cool that fish can be trained.  You have to wonder what's going through their tiny brains once they find out they can control where the car goes.  I'd like to think that it's the fish version of "Yeeeeee-haw!"

But what's next?  Maybe I can get them to come teach my dogs to mow my lawn.  It's about time they learn a useful skill.  (The dogs, not the researchers.)  On the other hand, now that I think about it, knowing my dogs they'd probably just use the lawn mower as a way of further terrorizing the local squirrels, so maybe it's better if they stay with all four feet on the ground.

*********************************

One of my favorite writers is the inimitable Mary Roach, who has blended her insatiable curiosity, her knowledge of science, and her wonderfully irreverent sense of humor into books like Stiff (about death), Bonk (about sex), Spook (about beliefs in the afterlife), and Packing for Mars (about what we'd need to prepare for if we made a long space journey and/or tried to colonize another planet).  Her most recent book, Fuzz: When Nature Breaks the Law, is another brilliant look at a feature of humanity's place in the natural world -- this time, what happens when humans and other species come into conflict.

Roach looks at how we deal with garbage-raiding bears, moose wandering the roads, voracious gulls and rats, and the potentially dangerous troops of monkeys that regularly run into humans in many places in the tropics -- and how, even with our superior brains, we often find ourselves on the losing end of the battle.

Mary Roach's style makes for wonderfully fun reading, and this is no exception.  If you're interested in our role in the natural world, love to find out more about animals, or just want a good laugh -- put Fuzz on your to-read list.  You won't be disappointed.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Black as the night

You wouldn't think that fish living three miles deep in the ocean, far beneath the level that sunlight can penetrate, would worry much about being seen.

Well, I'm not sure they're worried, exactly.  But they still have the problem that if they do somehow get seen, they're likely to get eaten.

This lies at the heart of the reason that bioluminescence exists in the deep ocean.  You probably know that bioluminescence is the ability of some organisms to use chemical reactions in their bodies to emit light.  (Fireflies are a common example.)  In the deep ocean, it was thought the main reason animals might do this is to create a lure; the illuminated "fishing pole" of the grotesque angler fish brings in curious smaller fish, which then get turned into lunch.

[Image licensed under the Creative Commons Masaki Miya et al., Bufoceratias, CC BY 2.0]

There are other functions for light-emitting structures besides lures.  Squid that live in shallow water have ink they squirt into the water then they're attacked, creating a dark cloud to confuse the predator, thus allowing the squid to escape.  But if you live at a depth where its perpetually dark, black ink is fairly useless; so there are deep-sea squid that emit luminescent ink, creating a burst of light to startle the predator and give the would-be dinner a chance to live for another day.

Last week in Current Biology, though, there was a paper wherein I learned about another reason for bioluminescence in the deep ocean.  In "Ultra-black Camouflage in Deep-Sea Fishes," by Alexander L. Davis, Sönke Johnsen, and Karen J. Osborn (Duke University), Kate N. Thomas (The London Museum of Natural History), Freya E. Goetz (Smithsonian National Museum of Natural History), and Bruce H. Robison (Monterey Bay Aquarium Research Institute), we read about fish like the evocatively-named fangtooth, Pacific blackdragon, and black swallower, whose skin is amongst the blackest naturally-occurring substances, reflecting less than 0.5% of the light the falls on it.

But as with the squid ink, why bother to evolve such dark skin if there's no light there to reflect?  The answer turns out to be that there is light there to reflect; the bioluminescence emitted by other predatory fish.  If you're in the complete darkness, even the reflection of a tiny amount of light from your body might give away your position.  So this is a third reason for deep-sea bioluminescence; not as a lure, nor a distraction, but as a searchlight.

These fish, however, are so dark that even in bright sunlight they look like black silhouettes, as study co-author Karen Osborn found out when she tried to photograph them.  This confers a significant advantage over other fish, even if there's only a marginal difference in the skin blackness.  The authors write:

At low light levels, as is the case with a fish reflecting <2% of an already dim source (i.e., a bioluminescent flash, lure, glow, or searchlight), against the black deep-sea background, the model predicts that the sighting distance is proportional to the square root of the number of photons being reflected back to the viewer.  Using this relationship, we find that reducing skin reflectance from 2% to 1% reduces sighting distance by 29% and that decreasing further to 0.5% or 0.05% reflectance reduces sighting distance by 50% and 84%, respectively.  Because visual predators typically search a volume of space, and this reduction in sighting distance is linear, the camouflage benefits of ultra-black skin may be even greater than the reduction in sighting distance calculated here.  Given the small size of the fishes studied here, it is likely that predator-prey interactions occur over short distances, where even small differences in sighting distance can have meaningful effects on interaction outcomes.

I've read that we know less about the abyssal regions of the ocean than we do about the surface of the Moon.  I don't know if that's true -- it's a little hard to quantify what we don't know about something -- but what's certain is that the deep ocean harbors some astonishingly weird creatures.  I'll end with a quote from H. P. Lovecraft, in whose writings the ocean represents everything that is dark and mysterious about the universe: "But more wonderful than the lore of old men and the lore of books is the secret lore of ocean...  The process of delving into the black abyss is to me the keenest form of fascination."

*************************************

This week's Skeptophilia book recommendation of the week is about as cutting-edge as you can get, and is as scary as it is fascinating.  A Crack in Creation: Gene Editing and the Unthinkable Power to Control Evolution, by Jennifer Doudna and Samuel Sternberg, is a crash course in the new genetic technology called CRISPR-Cas9 -- the gene-editing protocol that Doudna herself discovered.  This technique allows increasingly precise cut-and-paste of DNA, offering promise in not just treating, but curing, deadly genetic diseases like cystic fibrosis and Huntington's disease.

But as with most new discoveries, it is not without its ethical impact.  The cautious are already warning us about "playing God," manipulating our genes not to eliminate disease, but to enhance intelligence or strength, to change personal appearance -- or personality.

A Crack in Creation is an unflinching look at the new science of gene editing, and tries to tease out the how much of what we're hearing is unwarranted fear-talk, and how much represents a genuine ethical minefield.  Doudna and Sternberg give the reader a clear understanding of what CRISPR-Cas9 is likely to be able to do, and what it won't, and maps out a direction for the discussion to take based on actual science -- neither panic and alarmism, nor a Panglossian optimism that everything will sort itself out.  It's a wonderful introduction to a topic that is sure to be much in the news over the next few years.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Hands down

One of the most frustrating arguments -- if I can dignify them by that name -- from creationists is that there are "no transitional fossils."

If evolution happened, they say, you should be able to find fossils of species that are halfway between the earlier form and the (different-looking) later form.  That's actually true; you should find such fossils, and we have.  Thousands of them.  But when informed of this, they usually retort with one of two idiotic responses: (1) that evolution predicts there should be "halfway" forms between any two species you pick, which is what gave rise to Ray "BananaMan" Comfort's stupid "crocoduck" and "doggit" (dog/rabbit blend) photoshop images you can find with a quick Google search if you're in the mood for a facepalm; or (2) that any transitional forms just makes the situation worse -- that if you're trying to find an intermediate between species A and species C, and you find it (species B), now you've gone from one missing transitional form to two, one between A and B and the other between B and C.

This always reminds me of the Atalanta paradox of the Greek philosopher Zeno of Elea.  The gist is that motion is impossible, because if the famous runner Atalanta runs a race, she must first reach the point halfway between her starting point and the finish line, then the point halfway between there and the finish line, then halfway again, and so on; and because there are an infinite number of those intermediate points, she'll never reach the end of the race.  Each little bit she runs just leaves an unending number of smaller distances to cross, so she's stuck.

Fortunately for Atalanta she spent more time training as a runner than reading philosophy, and doesn't know about this, so she goes ahead and crosses the finish line anyway.

But back to evolution.  The problem with the creationists' "transitional fossil" objection is that just about every time paleontologists find a new fossil bed, they discover more transitional fossils, and often find species with exactly the characteristics that had been predicted by evolutionary biologists before the discovery.  And that's the hallmark of a robust scientific model; it makes predictions that line up with the actual facts.  Transitional fossils are an argument for evolution, not against it.

We got another illustration of the power of the evolutionary model with a paper last week in Nature, authored by Richard Cloutier, Roxanne Noël, Isabelle Béchard, and Vincent Roy (of the Université du Québec à Rimouski), and Alice M. Clement, Michael S. Y. Lee, and John A. Long (of Flinders University).  One of the most striking homologies between vertebrates is their limbs -- all vertebrates that have limbs have essentially the same bone structure, with one upper arm bone, two lower arm bones, and a mess of carpals, metacarpals, and phalanges.  Doesn't matter if you're looking at a bat, a whale, a dog, a human, or a frog, we've all got the same limb bones -- and in fact, most of them have not only the same bones, but the same number in the same positions.  (I've never heard a creationist come up with a good explanation for why, if whales and humans don't have a common ancestor, whales' flippers encase a set of fourteen articulated finger bones -- just like we have.)

In any case, it's been predicted for a long time that there was a transitional form between fish and amphibians that would show an intermediate between a fish's fin and an amphibian's leg, but that fossil proved to be elusive.

Until now.

Readers, meet Elpistostege.  As far as why it's remarkable, allow me to quote the authors:

The evolution of fishes to tetrapods (four-limbed vertebrates) was one of the most important transformations in vertebrate evolution.  Hypotheses of tetrapod origins rely heavily on the anatomy of a few tetrapod-like fish fossils from the Middle and Late Devonian period (393–359 million years ago). These taxa—known as elpistostegalians—include Panderichthys, Elpistostege, and Tiktaalik, none of which has yet revealed the complete skeletal anatomy of the pectoral fin.  Here we report a 1.57-metre-long articulated specimen of Elpistostege watsoni from the Upper Devonian period of Canada, which represents—to our knowledge—the most complete elpistostegalian yet found.  High-energy computed tomography reveals that the skeleton of the pectoral fin has four proximodistal rows of radials (two of which include branched carpals) as well as two distal rows that are organized as digits and putative digits.  Despite this skeletal pattern (which represents the most tetrapod-like arrangement of bones found in a pectoral fin to date), the fin retains lepidotrichia (fin rays) distal to the radials.  We suggest that the vertebrate hand arose primarily from a skeletal pattern buried within the fairly typical aquatic pectoral fin of elpistostegalians.  Elpistostege is potentially the sister taxon of all other tetrapods, and its appendages further blur the line between fish and land vertebrates.

Well, that seems like a slam-dunk to me.  An amphibian-like limb bone arrangement -- with fish-like fin rays at the end of it.

No transitional forms, my ass.

[Image licensed under the Creative Commons Placoderm2, Elpistostege watsoni, CC BY-SA 4.0]

Study lead author Richard Cloutier said basically the same thing, but more politely, in an interview with Science Daily: "The origin of digits relates to developing the capability for the fish to support its weight in shallow water or for short trips out on land.  The increased number of small bones in the fin allows more planes of flexibility to spread out its weight through the fin...  The other features the study revealed concerning the structure of the upper arm bone or humerus, which also shows features present that are shared with early amphibians.  Elpistostege is not necessarily our ancestor, but it is closest we can get to a true 'transitional fossil', an intermediate between fishes and tetrapods."

So there you have it.  Evolution delivers again.  I'm not expecting this will convince the creationists -- probably nothing would -- but at least it's one more fantastic piece of evidence for anyone who's on the fence.  Now y'all'll have to excuse me, because I'm off to the kitchen to get another cup of coffee, and it's going to take me an infinite amount of time to get there, so I better get started.

*******************************

In the midst of a pandemic, it's easy to fall into one of two errors -- to lose focus on the other problems we're facing, and to decide it's all hopeless and give up.  Both are dangerous mistakes.  We have a great many issues to deal with besides stemming the spread and impact of COVID-19, but humanity will weather this and the other hurdles we have ahead.  This is no time for pessimism, much less nihilism.

That's one of the main gists in Yuval Noah Harari's recent book 21 Lessons for the 21st Century.  He takes a good hard look at some of our biggest concerns -- terrorism, climate change, privacy, homelessness/poverty, even the development of artificial intelligence and how that might impact our lives -- and while he's not such a Pollyanna that he proposes instant solutions for any of them, he looks at how each might be managed, both in terms of combatting the problem itself and changing our own posture toward it.

It's a fascinating book, and worth reading to brace us up against the naysayers who would have you believe it's all hopeless.  While I don't think anyone would call Harari's book a panacea, at least it's the start of a discussion we should be having at all levels, not only in our personal lives, but in the highest offices of government.

The social context of animals

One misperception about the world that has proven to be awfully persistent is that there's some kind of qualitative difference between humans and the rest of the natural world.

Even our signature ability -- problem solving and rational thought, i.e., intelligence -- is a difference in degree and not in type.  The other primates show tremendous ability to problem solve, and "higher-order thinking" has been seen not only in our near relatives but in corvids (crows and ravens) and octopuses (which seem to be the brainiest invertebrates by far).

And before we start congratulating ourselves on being the smartest beings on the planet, it must be said that we're also the only ones using what intelligence we have to completely destroy the place.

So the whole "human vs. animal" distinction I still hear people talking about is really pretty meaningless.  Every difference you can come up with between humans and our non-human relatives is a shared in some way with other animals, even if it's not to the same degree or expressed the same way.

Our sense of having a bunch of special characteristics got another blow last week from two studies out of the Max Planck Institute in Germany, one of Vulturine Guineafowl (Acryllium vultinurum) and the other of golden shiner fish (Notemigonus crysoleucas).  And both of them point at the same conclusion -- another feature of the human species we like to consider unique to humanity, complex social structure, isn't unique to us at all.

The first study is called "Multilevel Society in a Small-Brained Bird," authored by a team led by Damian Farine.  The title of the paper sounds like an unwarranted cheap shot until you see a picture of the bird itself:

[Image licensed under the Creative Commons https://commons.wikimedia.org/wiki/File:Vulturine_Guineafowl_-_Samburu_-_KenyaNH8O7020_(15362431600).jpg]

You have to admit that this is a pretty spectacular brain-to-body-size ratio.  And frankly, the bird's actual name -- "Vulturine Guineafowl" -- isn't all that complimentary, either.

Be that as it may, Farine's team found that the interactions of these highly social birds were way more complex than they looked.  The four hundred individuals in the population they studied consisted of eighteen subgroups made up of between thirteen and sixty-five individuals each, and even though there was some mixing of the groups during feeding and roosting, overall the cliques were remarkably stable.  Guineafowl preferentially associate with certain individuals, and make long-lasting bonds with each other that are not apparently based on one of the two usual reasons -- sex/pair bonding and kinship.

In other words: guineafowls have buddies.

"To our knowledge, this is the first time a social structure like this has been described for birds," said Danai Papageorgiou, lead author of the paper.  "It is remarkable to observe hundreds of birds coming out of a roost and splitting up perfectly into completely stable groups every single day.  How do they do that?  It’s obviously not just about being smart."

Had to get in another dig about brain size, didn't you, Dr. Papageorgiou?

The other study, titled "Individual and Collective Encoding of Risk in Animal Groups," was authored by a team led by Iain Couzin, and studied an animal generally considered to be even less intelligent than guineafowl -- a schooling species of fish called a golden shiner.

What the researchers did is to generate "startle events" in schools of shiners by squirting a compound into the water called schreckstoff (which literally translates to "fear stuff" -- gotta love German words), which is produced naturally by the skin of individuals when they're injured.  This chemical acts as a pheromone-like signal that there's danger nearby, and generates alarm behavior in the entire school.

The surprise came when the researchers found that the strength of the startle event wasn't a function of the amount of schreckstoff in the water, it was a function of the physical structure of the school.  If the school itself was spread out, a small amount of schreckstoff generated strong startle behavior.  When the fish were close to their schoolmates, they didn't startle nearly so easily.

The comparison to the human phenomenon of "courage in numbers" is obvious.

"Making each individual more sensitive to risk can lead to an excessive number of false alarms propagating through the group," said study lead author Couzin.  "On the other hand, strengthening social connections allows individuals to amplify information about risk, but buffers against the system becoming overly sensitive."

So other animals -- even fish and small-brained birds -- share a great many features with ourselves.  This comes as no surprise to evolutionary biologists, who see all of life as on a giant connected spectrum anyhow.  But these two studies suggests there are more commonalities between humans and other animals in terms of social complexity than we realized.

"We have traditionally assumed that intelligence resides in our brains, in the individual animal," Couzin said.  "But we have found the first evidence that intelligence can also be encoded in the hidden network of communication between us."

**********************************

This week's Skeptophilia book recommendation is a fun book about math.

Bet that's a phrase you've hardly ever heard uttered.

Jordan Ellenberg's amazing How Not to Be Wrong: The Power of Mathematical Thinking looks at how critical it is for people to have a basic understanding and appreciation for math -- and how misunderstandings can lead to profound errors in decision-making.  Ellenberg takes us on a fantastic trip through dozens of disparate realms -- baseball, crime and punishment, politics, psychology, artificial languages, and social media, to name a few -- and how in each, a comprehension of math leads you to a deeper understanding of the world.

As he puts it: math is "an atomic-powered prosthesis that you attach to your common sense, vastly multiplying its reach and strength."  Which is certainly something that is drastically needed lately.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

In the swim

The ability to swim didn't evolve until amazingly late, especially considering that for the first two billion years, life on Earth was pretty much confined to the oceans.

It wasn't until the Devonian Era, which began 420 million years ago, that swimming animals dominated the seas.  There were a few swimming species prior to that, but far and away the most common life forms were benthic -- confined to the sea floor -- or planktonic, free-floating and at the mercy of the currents.

Then, according to the conventional wisdom, something changed.  It's been nicknamed the "Devonian nektonic revolution" (nektonic means actively swimming).  But a recent piece of research suggests that it may not have been that simple.

Christopher Whalen and Derek Briggs, of the Yale University Department of Geology and Geophysics, did a thorough analysis of what is known from the fossil record, and looked at how the morphology of animals indicated whether they were swimmers, benthic, or planktonic.  And their results suggests that the "Devonian nektonic revolution" never happened -- swimming evolved in the Cambrian Era, a hundred or so million years earlier, and swimmers experienced a gradual increase as they outcompeted more sedentary forms.  Throughout that time, Whalen says, "the water column was slowly filling with larger, more actively swimming animals...  By the end of the Paleozoic, the oceans looked more like the oceans we know today."

Although some things have changed since then.  Fortunately.  Consider the six meter long, one ton Devonian top-tier predator, Dunkleosteus, surely one of the most badass fish ever evolved.

[Image licensed under the Creative Commons, Creator:Dmitry Bogdanov, Dunkleosteus intermedius, CC BY 3.0]

I'm just as happy swimming in an ocean that doesn't have these mofos swimming around, thank you very much.

Another cool paper about the life aquatic comes from Arizona State University, where behavioral ecologist Nobuaki Mizumoto did some analysis on a unique fossil that captures an entire school of tiny fish, and determined that schooling behavior had evolved by the Eocene Epoch (50 million years ago) and even back then operated by the same "rules of attraction and repulsion" that govern schooling and flocking today -- keeping an optimal distance from your near neighbors, just right to avoid collisions but benefit from the predator-avoidance aspect of sticking with the group.

It's uncertain what killed the entire school, but as the fossil is in sandy limestone, it could be that an underwater dune or hill face collapsed and smothered them.  What is remarkable is that it apparently happened quickly enough that they were preserved pretty much in situ -- essentially in their original positions in the school.

Mizumoto, along with co-authors Shinya Miyata and Stephen Pratt, write:

We found traces of two rules for social interaction similar to those used by extant fishes: repulsion from close individuals and attraction towards neighbours at a distance.  Moreover, the fossilized fish showed group-level structures in the form of oblong shape and high polarization, both of which we successfully reproduced in simulations incorporating the inferred behavioural rules.  Although it remains unclear how the fish shoal's structure was preserved in the fossil, these findings suggest that fishes have been forming shoals by combining sets of simple behavioural rules since at least the Eocene.  Our study highlights the possibility of exploring the social communication of extinct animals, which has been thought to leave no fossil record.

It's unusual when a fossil allows us to infer anything about behavior -- patterns of tracks can tell us about whether an animal traveled in groups, but it's a rare fossil that gives us anything but guesses.  So this study is unique in that it gives us a window into how this tiny species of Eocene fish behaved when it was alive.

So that's our investigation into the paleontology of swimming.  Amazing how much we can tell from a careful analysis of fossils -- giving us a window into a world that's been gone for millions of years.

***********************************

In 1919, British mathematician Godfrey Hardy visited a young Indian man, Srinivasa Ramanujan, in his hospital room, and happened to remark offhand that he'd ridden in cab #1729.

"That's an interesting number," Ramanujan commented.

Hardy said, "Okay, and why is 1729 interesting?"

Ramanujan said, "Because it is the smallest number that is expressible by the sum of two integers cubed, two different ways."

After a moment of dumbfounded silence, Hardy said, "How do you know that?"

Ramanujan's response was that he just looked at the number, and it was obvious.

He was right, of course; 1729 is the sum of one cubed and twelve cubed, and also the sum of nine cubed and ten cubed.  (There are other such numbers that have been found since then, and because of this incident they were christened "taxicab numbers.")  What is most bizarre about this is that Ramanujan himself had no idea how he'd figured it out.  He wasn't simply a guy with a large repertoire of mathematical tricks; anyone can learn how to do quick mental math.  Ramanujan was something quite different.  He understood math intuitively, and on a deep level that completely defies explanation from what we know about how human brains work.

That's just one of nearly four thousand amazing discoveries he made in the field of mathematics, many of which opened hitherto-unexplored realms of knowledge.  If you want to read about one of the most amazing mathematical prodigies who's ever lived, The Man Who Knew Infinity by Thomas Kanigel is a must-read.  You'll come away with an appreciation for true genius -- and an awed awareness of how much we have yet to discover.

[Note: If you purchase this book using the image/link below, part of the proceeds will go to support Skeptophilia!]

The face in the mirror

One of the most relied-upon tests of animal intelligence is the mirror test.  The idea is to see if an animal realizes that its reflection in a mirror is itself, or if it thinks it's another animal.  A lot of primates pass the mirror test -- if you put a mark on a chimp's cheek and show it its reflection, it will immediately reach toward its cheek to wipe off the mark rather than reach toward the reflection.

Most dogs don't pass the mirror test, but some can.  My hyper-intelligent but emotionally-conflicted border collie/coonhound cross, Doolin, barked at her own reflection -- once.  Confronted with a full-length mirror, she went into attack-the-intruder mode, for about five seconds, then fell silent, and kind of did a doggie shrug.  "Oh," she seemed to think.  "I get it.  That's me."  And she never barked at her reflection again.

My bluetick/redbone hound Lena, though -- who is, to put it kindly, on the opposite side of the intelligence spectrum from Doolin -- spends many hours in the summer entertaining herself by barking at her own reflection in our pond.  "I'll get you, Water Dog!  Get out of my pond immediately!"

She also spent a long time barking furiously at something out in the yard last summer.  I went to investigate, thinking she might have cornered a groundhog or something, and it turned out to be a stick.

To be fair, it was a pretty threatening-looking stick, but still.

In general, most other animals can't pass the mirror test.  Male betta fish, for example, will hurl themselves at a reflection until they injure themselves.  But new research from Osaka City University, led by behaviorist Masanori Kohda, suggests that some fish might be a good bit cleverer.

Cleaner wrasses (Labroides spp.) are a group of small marine fish that make a living picking and eating parasites from other fish.  Such behavior isn't necessarily indicative of intelligence; there are also cleaner shrimp that do the same thing and don't show any particular sign of extraordinary brainpower.  But the wrasses in Kohda's aquarium showed an interesting response when confronted with a mirror.  First, they attacked the reflection, but that behavior died down after a few days (it never does with bettas).  But instead of simply ignoring the reflection -- which might indicate they'd just given up trying to chase the intruder off -- the wrasses began swimming upside down in front of the reflection, as if they were inspecting themselves from another angle.

Bluestreak Cleaner Wrasse [Image is in the Public Domain]

So Kohda and his team wondered if this might be an indication that wrasses could pass the mirror test.  They took some wrasses and marked the underside of their throats, and put them in front of a mirror.  Instead of trying to pick the mark off their reflection, they scraped their throats on the bottom of the tank -- as if they'd recognized the mark was on themselves and were trying to rub it off.

Not all scientists are convinced by this evidence, however.  "True, self-scraping is not a behavior one would expect if these fish interpret their reflection as another individual, but is this enough reason to conclude that they perceive the fish in the mirror as themselves?" wrote Frans de Waal, the brilliant Dutch animal behaviorist in a response to the Kohda et al. study.  "After all, the most compelling evidence for the latter would be unique behavior never seen without a mirror, whereas self-scraping, or glancing, is a fixed action pattern of many fish.  We may need an in-depth study of this particular pattern before we can ascertain what it means when performed in front of a mirror."

The study is pretty suggestive, though, and it's to be hoped that there'll be more research to see if it's supported, or if (as de Waal mentions) it might just be a complex fixed action pattern.  In any case, I need to wrap this up, because Lena is outside barking her head off.  Maybe she's cornered a highly vicious leaf or something, I dunno.

********************************

Humans have a morbid fascination with things that are big and powerful and can kill you.  Look at the number of movies made and books written about tornadoes, hurricanes, earthquakes, and volcanoes, not to mention hordes of predatory dinosaurs picking people off the streets.  But in the "horrifically dangerous" category, nothing can beat black holes -- collapsed stars with a gravitational field so strong not even light can escape.  If you fell into one of these things, you'd get "spaghettified" -- stretched by tidal forces into a long, thin streamer of goo -- and every trace of you would be destroyed so thoroughly that they'd not even be theoretically possible to retrieve.

Add to that the fact that because light can't escape them, you can't even see them.  Kind of makes a pack of velociraptors seem tame by comparison, doesn't it?

So no wonder there are astrophysicists who have devoted their lives to studying these beasts.  One of these is Shep Doeleman, whose determination to understand the strangest objects in the universe is the subject of Seth Fletcher's wonderful book Einstein's Shadow: A Black Hole, a Band of Astronomers, and the Quest to See the Unseeable.  It's not comfortable reading -- when you realize how completely insignificant we are on the scale of the universe, it's considerably humbling -- but it'll leave you in awe of how magnificent, how strange, and how beautiful the cosmos is, and amaze you that the human brain is capable of comprehending it.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

Fish tales

Today's topic comes from Cool News in Paleontology.

I was alerted to this story because I was perusing science research sites and saw a photograph that looked, to my untrained eye, like a Croc shoe with eyes and a pine cone stuck on the heel.  After saying, "What the hell is that?" I found that it was a reconstruction of a primitive vertebrate called a placoderm, or armored fish.  Lest you think my description is an exaggeration, there's the beast that caught my eye:

This led me to a paper in Science called "The Nearshore Cradle of Early Vertebrate Diversification," by Lauren Sallan, Matt Friedman, Robert S. Sansom, Charlotte M. Bird, and Ivan J. Sansom, wherein I found that this was by far not the weirdest-looking reconstructed critter in the study.  Here are a few others (all reconstructions by Nobumichi Tamura):

I particularly like the one on the lower left, which looks to me like someone took a fish and stuffed its head in a funnel.  I don't know why any of these other species became extinct, but I'm guessing the one on the lower left looked in the mirror and died of sheer embarrassment.

The research, though, is pretty damn cool.  The authors write:

Ancestral vertebrate habitats are subject to controversy and obscured by limited, often contradictory paleontological data.  We assembled fossil vertebrate occurrence and habitat datasets spanning the middle Paleozoic (480 million to 360 million years ago) and found that early vertebrate clades, both jawed and jawless, originated in restricted, shallow intertidal-subtidal environments.  Nearshore divergences gave rise to body plans with different dispersal abilities: Robust fishes shifted shoreward, whereas gracile groups moved seaward.  Fresh waters were invaded repeatedly, but movement to deeper waters was contingent upon form and short-lived until the later Devonian.  Our results contrast with the onshore-offshore trends, reef-centered diversification, and mid-shelf clustering observed for benthic invertebrates.  Nearshore origins for vertebrates may be linked to the demands of their mobility and may have influenced the structure of their early fossil record and diversification.

They also bring up an interesting conjecture; that the tougher anatomy, and especially the presence of a backbone to protect the dorsal nerve cord, might have arisen because of the rough-and-tumble nature of near-shore ecosystems -- you have to be tough or you'll get battered to pieces by the waves.

That, in fact, is why this study was such a mammoth undertaking.  "The main problem is that the fossil record [of vertebrates] is absolutely terrible for the first fifty million to one hundred million years of their existence," said paleobiologist Lauren Sallan of the University of Pennsylvania, in an interview with Science News.  "And when [there are] fossils, they’re in tiny pieces.  It’s hard to tell what exactly’s going on."

The researchers put together the pieces of 2,827 fossils that date to the age range they were studying, and came to the conclusion that all vertebrates trace their lineage back to shallow, near-shore environments.  So maybe I shouldn't laugh at Pine Cone Butt and the Spotted Funnel-Head.  They could be my great-great-great (etc.) grandparents.

I've always had a fascination for paleontology, and this study impresses me not only for its breadth but for what it tells us about our own ancestry.  The forces of evolution have created some amazing-looking creatures, and it's wonderful that we're getting a look into where they may have lived.  It does bear mention, however, that even with the thoroughness of the Sallan et al. study, we're still barely scratching the surface.  We only know about the species that left fossils behind -- which by some estimates is less than a hundredth of a percent of the species that were around at any given time.

So imagine what it would be like to go back there and see it for yourself, back to a time when there was not a single species of plant or animal around that exists today.  Mind-blowing, no?  As the old adage goes, the only thing that is constant is change -- and that is especially true with the natural world.

***********************************

The Skeptophilia book recommendation of the week is a must-read for anyone interested in languages -- The Last Speakers by linguist K. David Harrison.  Harrison set himself a task to visit places where they speak endangered languages, such as small communities in Siberia, the Outback of Australia, and Central America (where he met a pair of elderly gentlemen who are the last two speakers of an indigenous language -- but they have hated each other for years and neither will say a word to the other).

It's a fascinating, and often elegiac, tribute to the world's linguistic diversity, and tells us a lot about how our mental representation of the world is connected to the language we speak.  Brilliant reading from start to finish.

Viral nonsense

I'm going to issue another plea to please please puhleeeezz check your sources before posting stuff.

This goes double for the viral meme type shit you see every single day on social media.  Most of that stuff -- and I'm not talking about the ones that were created purely for the humor value -- is the result of someone throwing together a few intended-to-be-pithy quotes with a photograph downloaded from the internet, so it's only as accurate as the person who made it.

In other words, not very.

Here's an example that I'm seeing all over the place lately:

Okay, let's take a look at this piece by piece.

1. Tilapia has bones.  Anyone who's ever prepared tilapia for cooking knows this.
2. It is an ordinary fish, with not only bones, but skin.  Note that the photograph of the damn fish right in the image shows that it has skin.
3. You can certainly overcook it, like you can with anything.  Leave it in the oven for three hours, and you'll have fish jerky.
4. Tilapia is found in the wild.  It's native to Africa.  Most tilapia being sold is raised on fish farms, so that part is correct, showing the truth of the old adage that even a stopped clock is right twice a day.
5. I'm not even sure what "the Algae & lake plant, or replaced by gmo soy & corn" means.  Maybe they're trying to say that farmed tilapia is sometimes fed genetically-modified soy or corn-based products, which could well be, but is completely irrelevant even if it's true.
6. Eating tilapia is not worse than bacon and hamburgers.  It's low in overall calories and saturated fats, and is a good source of protein.
7. It'd be odd if tilapia were unusually high in dioxins, as dioxins are produced by such activities as burning plastic.  In fact, according to Medical News Today, due to EPA regulations, the amount of dioxins in the environment in the USA is 90% reduced from what it was thirty years ago -- and they recommend eating fish as a way of decreasing the amount of dioxin in your diet.
8. Dioxin "can take up to 11 years to clear?"  Not ten or twelve?  Okay, now you're just pulling this out of your ass.
9. You are not killing your family by serving them tilapia.  For fuck's sake.

Then, there's this nonsense that I've seen over and over:

Just out of curiosity, how desperate do you have to be to photoshop Trump into a photograph in order to make him look like a compassionate human being?  I mean, I get that there's not much else you can do.

But still.

If you're curious, the photograph doesn't even come from Hurricane Florence (as the post claims, along with a snarky "You won't see this on the news -- share with everyone!" caption).  It comes from the 2015 flooding in Texas.  Here's the unaltered photo:

I do think it's kind of inadvertently hilarious that when they photoshopped Trump into the picture, they made it look like he's handing the guy a MAGA hat.  "Hey, thanks for being here.  I was expecting more people to show up and applaud me, but I guess the killer flood swept them away.  Here, have a hat."


Then there's latest craze from Gwyneth "Snake Oil" Paltrow's company Goop, which is: "wearable stickers."  Me, I thought all stickers were wearable in the sense that you can stick them to your skin.  Thus the name.

But that's not what she's talking about.  These stickers, which are a "major obsession around Goop HQ," are supposed to "rebalance the energy frequencies in your body."

Whatever the fuck that means.

Here's a photo of a woman with three of them on her arm:

And the sales pitch:

Human bodies operate at an ideal energetic frequency, but everyday stresses and anxiety can throw off our internal balance, depleting our energy reserves and weakening our immune systems.  Body Vibes stickers come pre-programmed to an ideal frequency, allowing them to target imbalances.  While you’re wearing them—close to your heart, on your left shoulder or arm—they’ll fill in the deficiencies in your reserves, creating a calming effect, smoothing out both physical tension and anxiety.  The founders, both aestheticians, also say they help clear skin by reducing inflammation and boosting cell turnover.

Which is nearly "tilapia is killing you" levels of bullshit.  Just to point out one thing -- because even explaining this far is giving Paltrow far more credit than she deserves -- there's no such thing as an "energy frequency" because energy and frequency are two entirely different things.  Saying "energy frequency" is like asking someone what their "weight speed" is.

So I'm begging you.  Do a quick search online before reposting this stuff.  There are a ton of fact-check and skeptical analysis sites where you can at least do a first-order look at whether there's any truth to it.  The only other way to approach this is to comment "THIS IS NONSENSE" every time you see things like this, and that's beginning to feel a little like trying to patch the hole in the Titanic with duct tape.

 *****************************

This week's recommendation is a classic.

When I was a junior in college, I took a class called Seminar, which had a new focus/topic each semester.  That semester's course was a survey of the Book Gödel, Escher, Bach: An Eternal Golden Braid by Douglas Hofstadter.  Hofstadter does a masterful job of tying together three disparate realms -- number theory, the art of M. C. Escher, and the contrapuntal music of J. S. Bach.

It makes for a fascinating journey.  I'll warn you that the sections in the last third of the book that are about number theory and the work of mathematician Kurt Gödel get to be some rough going, and despite my pretty solid background in math, I found them a struggle to understand in places.  But the difficulties are well worth it.  Pick up a copy of what my classmates and I came to refer to lovingly as GEB, and fasten your seatbelt for a hell of a ride.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]