The oasis

I've always thought it was astonishing that anything short of extremely cold-adapted species could make it through an ice age.

During the last major glacial period, which peaked about twenty-one thousand years ago, the spot where I'm sitting right now was under a thirty-meter-thick layer of ice.  In fact, the hills about fifty kilometers south of us -- the Elmira Moraine -- marks the terminus of the glacier, where rocks, gravel, and soil that had been pushed forward by the advancing ice sheet got left behind as it melted.  During this period, the average global temperature was 6 C colder than it is now, and so much water was locked up as ice that the sea level was over a hundred meters lower than it is today.

My picture of how species survived (excluding the aforementioned cold-lovers) was that everything shifted range toward lower latitudes as the temperature cooled and the ice advanced, then reversed the process as the glacial period ended and the ice receded.  Species that couldn't shift quickly enough, or for which the climatic changes happened too fast to adapt, became extinct.  But according to a paper last week in Science Advances, the picture may not have been quite so simple.

One clue that our understanding was incomplete had to do with genetic diversity.  For a lot of species, we have a pretty good understanding of how quickly genetic mutations accrue, so looking at the genetic makeup of various populations within a species gives you an estimate of how long ago they had a common ancestor.  (And also tells you how closely each of those populations are related to the others.)  And in Europe, the populations of warmth-loving tree species like oaks suggested strongly that modern individuals weren't all descended from southern survivors which gradually expanded their ranges back northward as the glacial period ended twenty-odd-thousand years ago.  Their genetic diversity was too high for that to be plausible -- and some of the northern populations of modern oaks seemed to be a genetic cluster only distantly related to their southern cousins.

Fossils from the Czech Republic strongly suggest that what happened was that patches of the original forest were able to survive, clustered around hot springs that even at the height of the glacial period never froze over.  Geologist Jan Hošek of the Czech Geological Survey, who was lead author of the paper, found fossils of warmth-loving tree species preserved in geyserite -- a sedimentary rock produces by hot water dissolving and then depositing layers of opaline silica on exposed surfaces.  The hot springs created an oasis covering an estimated fifty square kilometers.  Not huge, but enough that a population of oaks and other temperate woodland plants (and presumably the animals they hosted) were able to survive the worst of the cold.

Artist's conception of the hot spring refugium [Image credit: artist Jiří Svoboda]

Being a warmth-lover myself, I always find it astonishing that species made it through some of these climatic extremes.  Not only the cold ones, of course; episodes like the Paleocene-Eocene Thermal Maximum, when the global temperature was 8 C above what it is now, can't have been pleasant, either.  But the recent discoveries show that given even a small refuge, living things will hang on despite all odds.

As Ian Malcolm famously put it, "Life, uh, finds a way."

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A refuge from the cold

I've always wondered how our distant ancestors survived during the various ice ages.

After all, we're mostly-hairless primates evolved on the warm, comfy African savanna, and it's hard to imagine how we coped with conditions like you often see depicted in books on early humans:

Le Moustier Neanderthals by Charles Knight (1920) [Image is in the Public Domain]

Despite the bear pelts around their nether regions, I've always wondered how they didn't all freeze to death.  When the weather's nice, bare skin is fine; I only wear a shirt during the summer under duress, and can't remember the last time I wore swim trunks when I went swimming in my pond.  But when the weather's cold -- which, here in upstate New York, is more often than not -- I'm usually wearing layers, and that's even indoors with our nice modern heating system.  Okay, admittedly I'm a wuss about the cold, but the fact remains that we're evolved to dwell in temperate regions.  Which, for a significant part of the Pleistocene Epoch, most of the world was not.

In particular, during the Last Glacial Maximum, between twenty-six and twenty thousand years ago, much of the Northern Hemisphere was experiencing a climate that the word "unpleasant" doesn't even begin to describe.  The average temperature was 6 C (11 F) colder than it is today, which was enough to cause ice sheets to spread across much of North America and northern Europe (where I currently sit, in fact, was underneath about thirty meters of ice).  Much of the non-glaciated land experienced not only dreadful cold, but long periods of drought.  The combined result is that the sea level was an estimated 130 meters lower than it is today, and broad dry valleys lay across what are now the bottoms of the Bering Sea, the North Sea and English Channel, and the Gulf of Carpentaria.

These conditions opened up passageways for some people, and closed off living space for others.  This was the time that the various pulses of immigrants crossed from Siberia through Beringia and into North America, where they became the ancestors of today's Indigenous Peoples of North and South America.  (If you want to read a brilliant account of how this happened, and some of the science behind how we know, you must read Jennifer Raff's wonderful book Origin: A Genetic History of the Americas.)  The same sort of thing happened from southeast Asia into what is now Australia.

In Europe, though, things got dicey to the point that it's a wonder anyone survived at all.  In fact, what brings this up is a study that appeared in Nature last week by a humongous team led by paleogeneticist Cosimo Posth of the Max Planck Institute of Evolutionary Anthropology.  The team did a complete genomic analysis of 356 individuals whose remains range from thirty-five thousand to five thousand years of age -- so right across that awful Last Glacial Maximum period -- to try to figure out how groups moved when the ice started coming in, and afterwards, once it retreated.

What they found was that only one part of Europe showed a consistent human genetic signature throughout the time period: the Iberian Peninsula.  What this indicates is that modern Spain and Portugal were a "climate refugium" during the worst of the glaciation, where people came to stay when the climate turned very cold, and pretty much stayed put.  Other areas that you might think were possible candidates for comparatively warm hideouts, such as what are now Italy and Greece, show a significant genomic shift across the Last Glacial Maximum, indicating that the people there before the cold set in either migrated or else died out, and were replaced by immigrants who moved in after things warmed and the area once again became more hospitable for humans.

"At that time, the climate warmed up quickly and considerably and forests spread across the European continent," said Johannes Krause, senior author of the study, in an interview with Science Daily.  "This may have prompted people from the south to expand their habitat.  The previous inhabitants may have migrated to the north as their habitat, the 'mammoth' steppe, dwindled,.  It is possible that the migration of early farmers into Europe triggered the retreat of hunter-gatherer populations to the northern edge of Europe.  At the same time, these two groups started mixing with each other, and continued to do so for around three thousand years."

Me, I'm curious what happened to these people afterward.  As a linguist, not to mention a white guy of western European descent, I've wondered if we're talking about my forebears, here -- and what languages they spoke.  My suspicion is that we're looking at the ancestors of today's Basques, who still live in northern Spain; they speak a non-Indo-European language that is usually considered a relic of the earliest languages spoken in Europe.  The Indo-European-speaking peoples (therefore the ancestors of the majority of today's Europeans) didn't reach Europe until about four thousand years ago, so long after the heyday of the people who were the subjects of the Posth et al. paper.

So you have to wonder who the descendants of these very early Europeans are.  "Not me" is my general assessment, considering my general cold-hardiness.  Drop me into an ice age where I had to live in a cave, hike on glaciers, hunt mammoth, and fend off cave bears, and I'd last maybe three days, tops.  I'm highly impressed by the ability of these ancient humans to survive, but given a choice I'll stick with my warm house, indoor plumbing, electric stove, and coffee maker.

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The stranded lagoon

When someone talks about getting a glimpse of prehistory from the modern landscape, usually what they're referring to is either (1) rocks, or (2) fossils.

There's no doubt that those are our best clues.  I saw a good example of this last weekend while we were visiting some friends in the Catskill Mountains.  We'd gone for a hike alongside the beautiful tumbling West Kill Creek, and I saw the unmistakable polished surface and parallel grooves of a slickenside -- a rock that had been carved and worn smooth by the passage of a glacier, probably the one that last covered this entire region on the order of twenty thousand years ago. 

Further back -- much further back -- the flaky, flat layers of gray shale and tan limestone that forms the majority of the bedrock around here is Devonian in age, something like three hundred million years old, when where I now sit was at the bottom of a shallow tropical ocean.  Those sediments were uplifted during the formation of the Appalachian Mountain range and have been slowly eroding ever since, with the outflow from the melting glaciers -- the same ones that left the scratches in the rocks I saw in the Catskills -- cutting the deep, steep-sided gorges this region is famous for.

Taughannock Falls -- right up the road from where I live

It turns out, though, that inferences about the past don't just come from rocks and fossils.  A much rarer, but even cooler, phenomenon comes from biology; it's called a relict population or peripheral isolate -- a cluster of individuals of a species left behind and/or cut off from the rest of the population by some major geological event.  An especially interesting one was just discovered recently, and was the subject of a paper in Proceedings of the National Academy of Sciences just published yesterday.  It concerns a clump of red mangrove trees (Rhizophora mangle) along the banks of the San Pedro Mártir River in the Yucatan Peninsula.  What tipped off the researchers that this was something weird was that red mangroves usually only grow in the brackish or salty shallows of tropical ocean shores -- and this one was 170 kilometers inland from the nearest mangrove marshes, along the banks of a freshwater river, with no individuals of that species in between.

Apparently what happened is that these mangroves were left behind after a warm period of high sea level ended.  As the temperature cooled and more ocean water was locked up in the form of ice, the seas receded, cutting off the little clump of mangroves from their cousins.

The authors write:

Climatic oscillations during the Pleistocene played a major role in shaping the spatial distribution and demographic dynamics of Earth's biota, including our own species.  The Last Interglacial (LIG) or Eemian Period (ca. 130 to 115 thousand years B.P.) was particularly influential because this period of peak warmth led to the retreat of all ice sheets with concomitant changes in global sea level.  The impact of these strong environmental changes on the spatial distribution of marine and terrestrial ecosystems was severe as revealed by fossil data and paleogeographic modeling.  Here, we report the occurrence of an extant, inland mangrove ecosystem and demonstrate that it is a relict of the LIG.  This ecosystem is currently confined to the banks of the freshwater San Pedro Mártir River in the interior of the Mexico–Guatemala El Petén rainforests, 170 km away from the nearest ocean coast but showing the plant composition and physiognomy typical of a coastal lagoon ecosystem.  Integrating genomic, geologic, and floristic data with sea level modeling, we present evidence that this inland ecosystem reached its current location during the LIG and has persisted there in isolation ever since the oceans receded during the Wisconsin glaciation.  Our study provides a snapshot of the Pleistocene peak warmth and reveals biotic evidence that sea levels substantially influenced landscapes and species ranges in the tropics during this period.

"This discovery is extraordinary," said biologist Felipe Zapata, of the University of California - Los Angeles, who co-authored the paper.  "Not only are the red mangroves here with their origins printed in their DNA, but the whole coastal lagoon ecosystem of the last interglacial has found refuge here."

 It's fascinating that you can use the distribution of a modern species to infer the conditions hundreds of thousands of years ago -- and, conversely, that the prehistoric climate and geology have left a distinct fingerprint on our current ecosystems.  It makes me wonder what the scientists of the far-distant future will be able to figure out about our world.  One of the ways that humans have changed things the most is the introduction of exotic species; in my part of the world, noxious pests like garlic mustard and Japanese beetles come to mind, but it bears mention that pigeons, dogs, cats, and horses are all introductions to North America that have established feral populations, as are most of the commonly consumed fruits (apples, peaches, pears, apricots, blackberries, raspberries, cherries, and all the citrus fruits), clover, dandelions, barberry, and just about all the species of grass you'd find in your lawn.

I wonder if future biologists will figure out how House Sparrows (Passer domesticus) got here, when their nearest relatives are all the way across the Atlantic Ocean.

The Earth, of course, is not done changing.  Even apart from what we're currently doing to the climate, there is the natural process of plate tectonics moving the continents around, altering patterns of ocean and air circulation with inevitable effects on the living ecosystems.  Piecing together what happened in the past can be done by looking at the present -- especially when you find a clump of trees that "shouldn't be there."

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During the first three centuries C.E., something remarkable happened; Rome went from a superpower, controlling much of Europe, the Middle East, and North Africa, to being a pair of weak, unstable fragments -- the Western and Eastern Roman Empires --torn by strife and internal squabbles, beset by invasions, with leaders for whom assassination was the most likely way to die.  (The year 238 C.E. is called "the year of six emperors" -- four were killed by their own guards, one hanged himself to avoid the same fate, and one died in battle.)

How could something like this happen?  The standard answer has usually been "the barbarians," groups such as the Goths, Vandals, Franks, Alans, and Huns who whittled away at the territory until there wasn't much left.  They played a role, there is no doubt of that; the Goths under their powerful leader Alaric actually sacked the city of Rome itself in the year 410.  But like with most historical events, the true answer is more complex -- and far more interesting.  In How Rome Fell, historian Adrian Goldsworthy shows how a variety of factors, including a succession of weak leaders, the growing power of the Roman army, and repeated epidemics took a nation that was thriving under emperors like Vespasian and Hadrian, finally descending into the chaos of the Dark Ages.  

If you're a student of early history, you should read Goldsworthy's book.  It's fascinating -- and sobering -- to see how hard it is to maintain order in a society, and how easy it is to lose it.

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

Dire straits

During my junior year as an undergraduate, I had to take a humanities elective as part of my degree requirements and settled upon a class in archaeology, a subject which had always been an interest of mine.  The course description sounded pretty cool, and I thought it would be a fun challenge to take on.

However, I had not reckoned with the fact that the professor, one Dr. Servello, seemed to have a screw loose.  I found this out early on when one day he caught a glimpse of some genealogical charts in my binder (part of a family tree project I was doing as an anniversary gift for my parents), and added that to the fact that I wore a St. Christopher medal, and concluded from this that I was a member of a cult.

He kept me after class that day to ask me what my cult believed.  When I protested that in fact, I did not belong to a cult, he became genuinely concerned and said, "No, no, you don't need to be afraid to tell me!  I'm fascinated by alternative belief systems!"

But the most striking thing about Dr. Servello was that he never admitted to being wrong.  About anything.  He had a nearly Trumpian ability to continue arguing his point even after having hard evidence that he'd misspoken thrown into his face.  One time he argued for a half-hour over the correct pronunciation of a Chinese archaeological site -- with a student from China.  In very short order we learned not to bother contradicting him about any of the wacky things he said, because it never accomplished anything but wasting inordinate amounts of class time.

But as in any group, in the class there was That Guy.  He felt duty-bound to challenge Dr. Servello every time he made shit up, which was usually several times per class.  But the one that stands out in my memory was the epic argument that ensued when Dr. Servello was telling us about dire wolves.

"It's one of the largest predatory mammals ever," he said, with great conviction.  "They were fourteen feet tall at the shoulder."

Simultaneously all of the two-dozen-odd students in the class gave Dr. Servello the human equivalent of the Canine Head Tilt of Confusion.  Even so, most of us just added it to our growing list of bizarre Servello-isms, and were prepared to let it go.

But not That Guy.

"That's impossible," he said flatly.

"No, no, they were huge!" Dr. Servello insisted.  "Biggest predatory mammal ever!"

"That's impossible," That Guy said through clenched teeth.  "A wolf that big could look into a second-story window."

There followed a good forty-five minute-long argument, ending with That Guy grabbing his binder and storming out of class.

I related the story to some friends later.  These friends always waited with bated breath for me to come out of archaeology class, to see what lunatic pronouncements Dr. Servello had made that day.  This one, however, was impressive even by comparison to his previous efforts.

"That," one of my friends said reverently, "is one big bow-wow."

The topic comes up because while dire wolves are not fourteen feet high at the shoulder (which, for the record, would make them taller than a full-grown male African elephant) they are a fascinating species.  They were pretty impressive animals -- adults averaged a meter high at the shoulder and a little over two meters from tip to tail -- but their skeletal morphology led taxonomists to believe they were simply larger cousins of the North American gray wolf, descended from a parental species that had crossed the Bering Land Bridge into Eurasia.  But that idea is being challenged by some new analysis of DNA from dire wolves who were trapped in the La Brea Tar Seeps forty-some-odd thousand years ago, and a comparison with gray wolf DNA supports a conclusion that the last common ancestry of the two species was around 5.7 million years ago, before the ancestors of today's gray wolves had crossed into North America.

Dire wolf skeleton in the Sternberg Museum, Hays, Kansas [Image licensed under the Creative Commons James St. John, Canis dirus Sternberg Museum, CC BY 2.0]

The research, which was the subject of a paper in Nature this week, suggests that the morphological similarities between gray wolves and dire wolves are due to convergent evolution -- the evolution of superficially similar traits in distantly-related species that are under the same selective pressures.  And of course, these two were starting out closer in structure anyhow; no one is doubting that dire wolves are canids.  But the DNA difference is striking enough that the researchers are proposing to take the dire wolf out of the genus Canis and place it in its own new genus -- Aenocyon, meaning "terrible wolf."

"These results totally shake up the idea that dire wolves were just bigger cousins of gray wolves," said paleontologist Grant Zazula, who was not involved in the new study, in an interview with Scientific American.  "The study of ancient DNA and proteins from fossil bones is rapidly rewriting the ice age and more recent history of North America’s mammals."

It is not, for the record, rewriting how big they were.  As terrible as Aenocyon was, it wouldn't have towered over an elephant.  However, it is thought to have had the greatest bite force of any canid ever, and as it seems to have been a pack hunter, could take down some of the megaherbivores of its time -- giant ground sloths, North American camels and horses, bison... and even mastodons.

But like most of the Ice Age megafauna, the changing climate at the end of the Pleistocene put the dire wolf in dire straits.  They're thought to have persisted in areas of the northern Rockies as little as 9,500 years ago, but when the big prey animals began to disappear, selection favored their smaller (now thought to be distant) cousins, gray wolves.

Which is kind of a shame.  They were impressive beasts, even if they weren't the big bow-wows Dr. Servello claimed they were.  And it's nice to clarify at least a little more of their genetics and history, turning a lens on a species we thought we understood.

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As a biologist, I've usually thought of myself as immune to being grossed out.  But I have to admit I was a little shocked to find out that the human microbiome -- the collection of bacteria and fungi that live in and on us -- outnumber actual human cells by a factor of ten.

You read that right: if you counted up all the cells in and on the surface of your body, for every one human cell with human DNA, there'd be ten cells of microorganisms, coming from over a thousand different species.

And that's in healthy humans.  This idea that "bacteria = bad" is profoundly wrong; not only do a lot of bacteria perform useful functions, producing products like yogurt, cheese, and the familiar flavor and aroma of chocolate, they directly contribute to good health.  Anyone who has been on an antibiotic long-term knows that wiping out the beneficial bacteria in your gut can lead to some pretty unpleasant side effects; most current treatments for bacterial infections kill the good guys along with the bad, leading to an imbalance in your microbiome that can persist for months afterward.

In The Human Superorganism: How the Microbiome is Revolutionizing the Pursuit of a Healthy Life, microbiologist Rodney Dietert shows how a lot of debilitating diseases, from asthma to allergies to irritable bowel syndrome to the inflammation that is at the root of heart disease, might be attributable to disturbances in the body's microbiome.  His contention is that restoring the normal microbiome should be the first line of treatment for these diseases, not the medications that often throw the microbiome further out of whack.

His book is fascinating and controversial, but his reasoning (and the experimental research he draws upon) is stellar.  If you're interested in health-related topics, you should read The Human Superorganism.  You'll never look at your own body the same way again.

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

Of rhinos and puppies

You're not alone if you immediately think "Africa" when you hear the word "rhinoceros."  The two largest and best-known species -- the black (Diceros bicornis) and white (Ceratotherium simum) rhinos -- are both native to the southern parts of Africa.  There are three additional extant species in southern Asia, however; the Indian (Rhinoceros unicornis), Javan (Rhinoceros sondaicus), and Sumatran (Dicerorhinus sumatrensis) rhinos.  The latter two are amongst the most endangered mammals in the world, with only about 60 and 245 individuals left, respectively.

Rhinos, though, used to be much more diverse, and much more common.  One of the most remarkable fossils ever discovered is the Blue Lake rhino, a fifteen-million-year-old cast of an extinct rhinoceros species called Diceratherium in what is now eastern Washington state.  The "remarkable" part is that it's fossilized in igneous rock, which isn't supposed to happen -- fossils are supposed to all be in sedimentary rock, right?  But what happened is there was a colossal eruption fifteen million years ago that produced the Columbia River Flood Basalts, releasing an estimated 174,000 cubic kilometers of lava, an amount that's hard to fathom.  Anyhow, this poor rhino was peacefully grazing, minding its own business, and suddenly BAM, it gets hit by a fast-moving, highly liquid lava flow, its body entombed then burned away.  Fast forward to 1935, when a fossil hunter named Haakon Friele discovered a strange cave in a basalt formation, crawled inside with a flashlight, and somehow thought, "Hey, this hole is shaped just like a rhino."  A bit later, a crew of paleontologists from the University of California - Berkeley were called in, and they made a plaster cast of the interior -- and sure enough, it's a cast of a very surprised-looking rhino who was very much in the wrong place at the wrong time.

There were other rhino species more recently, however.  The woolly rhinoceros (Coelodonta antiquitatis) was an ice-age species that lived pretty much everywhere in what is now Asia and Europe, but started declining in population about forty thousand years ago, dwindling until only a remnant population was left in Siberia.  The last ones died fourteen thousand years ago, give or take.

[Image licensed under the Creative Commons ДиБгд, Wooly Rhino15, CC BY-SA 4.0]

The blame for the woolly rhino's demise has been attributed to overhunting by early humans, but recent research suggests the cause was actually climate change.  In the paper, "Pre-Extinction Demographic Stability and Genomic Signatures in the Woolly Rhinoceros," by a team led by Edana Lord of the Swedish Museum of Natural History, we read the following:

Ancient DNA has significantly improved our understanding of the evolution and population history of extinct megafauna.  However, few studies have used complete ancient genomes to examine species responses to climate change prior to extinction.  The woolly rhinoceros (Coelodonta antiquitatis) was a cold-adapted megaherbivore widely distributed across northern Eurasia during the Late Pleistocene and became extinct approximately 14 thousand years before present (ka BP).  While humans and climate change have been proposed as potential causes of extinction, knowledge is limited on how the woolly rhinoceros was impacted by human arrival and climatic fluctuations.  Here, we use one complete nuclear genome and 14 mitogenomes to investigate the demographic history of woolly rhinoceros leading up to its extinction.  Unlike other northern megafauna, the effective population size of woolly rhinoceros likely increased at 29.7 ka BP and subsequently remained stable until close to the species’ extinction.  Analysis of the nuclear genome from a ∼18.5-ka-old specimen did not indicate any increased inbreeding or reduced genetic diversity, suggesting that the population size remained steady for more than 13 ka following the arrival of humans.  The population contraction leading to extinction of the woolly rhinoceros may have thus been sudden and mostly driven by rapid warming in the Bølling-Allerød interstadial.

So at least that's one calamity we're not responsible for.

On the other hand, another recent discovery shows that we might not have doomed the woolly rhino, but our best friends might have had a hand -- um, a paw -- in it.  A friend and long-time loyal reader of Skeptophilia sent me a link to an article about a mummified body of a dog found in Siberia that, when analyzed, was found to have bits of meat from a woolly rhino it its stomach.  "This puppy, we know already, has been dated to roughly 14,000 years ago," said researcher Love Dalén, also of the Swedish Museum of Natural History.  "We also know that the woolly rhinoceros goes extinct 14,000 years ago.  So, potentially, this puppy has eaten one of the last remaining woolly rhinos."

Dogs: Eating Stuff They Shouldn't Eat For the Past Fourteen Thousand Years.

So that's today's excursion into weird cul-de-sacs of zoology.  And honestly, I'm just as glad the temperate-area rhino species are gone, cool as they undoubtedly were.  We have enough trouble keeping the groundhogs and rabbits out of the vegetable garden, I can't imagine how we'd deal with rhinos tromping around the place.

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Fan of true crime stories?  This week's Skeptophilia book recommendation of the week is for you.

In The Poisoner's Handbook:Murder and the Birth of Forensic Medicine in Jazz Age New York, by Deborah Blum, you'll find out about how forensic science got off the ground -- through the efforts of two scientists, Charles Norris and Alexander Gettler, who took on the corruption-ridden law enforcement offices of Tammany Hall in order to stop people from literally getting away with murder.

In a book that reads more like a crime thriller than it does history, Blum takes us along with Norris and Gettler as they turned crime detection into a true science, resulting in hundreds of people being brought to justice for what would otherwise have been unsolved murders.  In Blum's hands, it's a fast, brilliant read -- if you're a fan of CSI, Forensics Files, and Bones, get a copy of The Poisoner's Handbook, you won't be able to put it down.

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

Unicorn survival

One of the arguments you'll hear from cryptid enthusiasts is that the various critters they claim are real are survivals.  Nessie, Mokele-Mbémbé, and the Bunyip are modern-day brachiosaurs or plesiosaurs.  Bigfoot, the Fouke Monster, the Almas, the Florida Skunk Ape, and the Yowie are hominids, possibly australopithecenes.  The Beasts of Bodmin Moor and Exmoor, and the Mngwa of Tanzania, are related to prehistoric cats.  Mothman is supposed to be... okay, I don't know what the fuck Mothman is supposed to be.  Maybe descended from the rare saber-toothed butterfly, I dunno.

[Nota bene: if you're curious about any of these and want more information, check out the excellent cryptid list on Wikipedia, which has these and many others, along with lots of highly amusing illustrations thereof.]

The possibility of prehistoric survival is not without precedent.  The most famous is the coelacanth, one of the bizarre lobe-finned fish found in fossil form in sediments from before the Cretaceous Extinction, 66-odd million years ago.  They were allied to the lineage that led to amphibians (although that split took place a lot longer ago, so they weren't direct ancestors), and had lobe-like proto-limbs that give the group their name.  They were thought to be long extinct -- until a fisherman off the coast of Madagascar caught one in 1938.

Even that iconic mammal of prehistory, the woolly mammoth, survived a lot longer than most people thought.  The last remnant populations were thought to have been in northern North America and Siberia on the order of 25,000 years ago -- until fossils were found on Wrangell Island, off the coast of Alaska, dating to around 3,800 years ago, making them contemporaneous with the building of the Great Pyramids of Egypt.

So it's always risky to date a bunch of fossils and conclude that the most recent one marks the end of the species.  Not only is fossilization uncommon (something I've touched upon before), but there can be small remnant populations left in out-of-the-way places, and our inferences about when species became extinct can be off.

Sometimes by a lot.  Take, for example, Elasmotherium, which was the subject of a paper in The American Journal of Applied Sciences that a friend and loyal reader of Skeptophilia sent me last week.  Elasmotherium has sometimes been nicknamed "the Siberian Unicorn," which is a little misleading, because the only similarities between it and the typical graceful, fleet-footed concept of the unicorn is that it had one horn and four legs.  Here's an artist's rendition of Elasmotherium:

[Image is in the Public Domain, courtesy of artist Heinrich Harder]

If your thought is that it looks more like a rhinoceros than a one-horned horse, you're correct; the elasmotheres are cousins to the modern African rhinos.  What's interesting about them is that they were around during the Pleistocene, reaching their peak during the repeated glaciations, and were thought to have died out as the climate warmed, on the order of 350,000 years ago -- but this study found fossils from Kozhamzhar in Kazakhstan that dated to around 26,000 years ago.

"Most likely, the south of Western Siberia was a refugium, where this rhino persevered the longest in comparison with the rest of its range," said Andrey Shpanski, a paleontologist at Tomsk State University, who co-authored the paper.  "There is another possibility that it could migrate and dwell for a while in the more southern areas."

So it's a good bet that the elasmotheres -- like the woolly mammoth -- persisted a lot longer than paleontologists realized.

This is the main reason why, despite my general skepticism, I'm hesitant to discount reports of cryptids out of hand.  That most of them are either hoaxes or else misidentification of perfectly ordinary modern animals seems pretty likely, but "most" doesn't mean "all."  I'm very much in agreement on this count with what astronomer Michio Kaku said about UFOs: "Perhaps 98% of sightings can be dismissed as fabrications or as perfectly natural phenomena.  But that still leaves 2% that are unaccounted for, and to me, that 2% is well worth investigating."

So I'm all for continuing to consider claims of cryptids, as long as we evaluate them based upon the touchstone for all scientific research: hard evidence.  It's entirely possible some animals thought previously to be extinct have survived in remote areas, and have given rise to what we now call cryptozoology.  If that's the case, though, it should be accessible to the tools of science -- and, truthfully, just be zoology, no "crypto" about it.

Except for Mothman.  That mofo is scary.  I'd just as soon that one stays in the realm of legend, thank you very much.

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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.

A rain of dust

One of the problems with the modern industrialized worldview -- and yes, I know this is an overgeneralization, but still -- is our tendency to think we're capable of controlling everything.

I'm not so much talking about simple day-to-day occurrences.  At least on a theoretical level, we're all aware we could get clobbered by a truck while crossing the road.  But the bigger stuff all seems so solid, so unshakeable, that it's hard to imagine it ever changing.  Of course the grocery stores will always have food, there'll always be electricity available when we plug in our toasters, water will flow when we turn on the faucet.  On an even bigger scale -- it'll be warm in the summer and cool in the winter, the crops will grow, the rain will fall.

You don't have to know much science -- or history, for that matter -- to realize how false this attitude is.  Even small perturbations to the global ecosystem can have drastic consequences.  (Just as a handful of examples -- the 1984-1985 drought in Ethiopia that left 1.2 million dead and 400,000 refugees; the drought in the Yucatán in the early 10th century C.E. that is thought to have caused the downfall of the Mayan Empire; and the American Dust Bowl of the 1930s. brought on by drought and lousy farming practices.)

The fact is -- and it's a point I've made before -- we need to be extraordinarily careful in pushing at the global ecosystem, because it can respond catastrophically to purely natural circumstances.  Adding global-scale human foolishness into the equation is a recipe for disaster.

As an example of how distant events can have unexpected global consequences, take the study published last week in Science Advances suggesting that a collision between two asteroids half a billion kilometers away triggered a drastic plunge in temperatures and the initiation of an ice age.  The event, which took place in the mid-Ordovician Period (466 million years ago), involved the destruction of an asteroid on the order of 150 kilometers in diameter, creating a dust plume that rained down upon the Earth.  The dust and debris blocking the sunlight triggered a drop in global temperatures and a sudden (geologically speaking) turnaround in the climate that spread ice sheets over much of the high latitudes in both hemispheres.

Of course, cosmic dust is falling into the Earth's atmosphere all the time, but this event caused a massive spike in the amount.  "Normally, Earth gains about 40,000 tons of extraterrestrial material every year," said study co-author Philipp Heck of the University of Chicago in an interview with Astronomy.  "Imagine multiplying that by a factor of 1,000 or 10,000."

The outcrop in Sweden that the researchers studied.  The layer containing the debris from the collision is visible as a gray line about 2/3 of the way up the cliff face.  [Image courtesy of Philipp Heck and the Field Museum]

The result of the cool-down was a huge increase in biodiversity as life forms evolved to cope with the change.  But before you start in on the "life finds a way" line of thought, and that this'll save us from the consequences of anthropogenic climate change, allow me to point out that the massive Ordovician chill was slower than today's warm-up by orders of magnitude.  "In the global cooling we studied, we're talking about timescales of millions of years," said Heck. "It's very different from the climate change caused by the meteorite 65 million years ago that killed the dinosaurs, and it's different from the global warming today — this global cooling was a gentle nudge.  There was less stress."

So yeah.  Having a thousand times the amount of dust flung at us from the explosion of an asteroid 150 kilometers across is still not as drastic as what we're currently doing to the climate.

Oh, and in a rather horrid coincidence, that quantity of debris is roughly equal to the amount of plastic we produced in 2015, 79% of which was landfilled.

So the idea that somehow the Earth is obligated to remain hospitable to human life regardless what we do to it -- or what happens outside of our sphere of control -- would be ludicrous if it weren't so terrifying.  It's why ham-handed efforts to "own the libs" by nitwits like Laura Ingraham (who tried to be funny by "attempting to drink a light-bulb stuffed steak using plastic straws") fall flat if you know anything at all about science.

Go ahead, Laura, laugh it up.  You better hope that we "libs" are overestimating the danger posed by the pro-industry, pro-fossil-fuels, damn-the-ecology-full-speed-ahead policies favored by people of your stripe.  And don't even start with me about how environmentally-conscious people are "hoping for disaster" or "trying to destroy the economy."  Fearing that something is likely to happen isn't the same as hoping it will happen, which should be clear to anyone who has an IQ larger than their shoe size and concern for anything other than short-term financial gain.

So once again, we have a piece of research about a distant event millions of years ago providing a cautionary tale about what's happening here and now.  I wish I had some kind of positive note to end this on, but increasingly, it's looking like our current behavior is likely to throw us past a tipping point -- and our long-term legacy might be appearing to some scientist in the distant future as a gray stripe in a rock outcrop.

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This week's Skeptophilia book recommendation is especially for those of you who enjoy having their minds blown.  Niels Bohr famously said, "Anyone who is not shocked by quantum theory has not understood it."  Physicist Philip Ball does his best to explain the basics of quantum theory -- and to shock the reader thereby -- in layman's terms in Beyond Weird: Why Everything You Thought You Knew About Quantum Physics is Different, which was the winner of the 2018 Physics Book of the Year.

It's lucid, fun, and fascinating, and will turn your view of how things work upside down.  So if you'd like to know more about the behavior of the universe on the smallest scales -- and how this affects us, up here on the macro-scale -- pick up a copy of Beyond Weird and fasten your seatbelt.

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