The Call of Distant Mammoths



I’ve long been interested in the megafauna extinctions of Pleistocene North America.  A number of books endorse Paul Martin’s “Pleistocene Overkill Hypothesis,” which asserts that the early humans on the continent were “super predators” who launched a blitzkrieg of overhunting.  Hunting began in northwest Canada, and spread south and east like a wild fire.  Within 2,000 years, at least 33 genera (50 species) of large mammals went extinct — many more than in the preceding three million years.  At first contact, large animals who had never before seen odd-looking humans, did not sense danger.

In other locations, when humans first arrived, extinctions followed — for example, Australia, New Zealand, Madagascar, and Caribbean islands.  Hunting, and hunting alone, was the cause, said Martin.  His ideas really pissed off Native Americans, like Vine Deloria, because overkill implied that Indians were as foolish as Euro Americans.

Deloria blasted the hypothesis, pointing to the fantastic number of bones found in northern Siberia — mammoths, mastodons, rhinos, horses, bison.  Chinese have been hauling away mammoth tusks since medieval times, and this ivory is still being mined today; a high-quality tusk can fetch over $40,000.  The white keys on grandma’s piano might be mammoth ivory.

These bones were not the result of a blitzkrieg.  Mastodons had been living in Siberia for 400,000 years, and woolly mammoths for 250,000 years.  The frigid climate helped to preserve their remains.  In central Russia, more than 70 mammoth bone huts have been found.  One hut had 385 bones, and weighed 20 tons.

I just read The Call of Distant Mammoths by paleontologist Peter Ward, and learned a lot about extinction and evolution.  I’ve often wondered how hairy lads, on foot, with wooden spears, were able to exterminate every horse in all of North America within 2,000 years.  Bison were also residents of the open plains, able to sprint up to 35 miles per hour, and they did not go extinct — and horses could run even faster.

Ward introduces us to the climate change hypothesis.  During the two million year Ice Age (the Pleistocene), there were at least 18 glaciation cycles.  Until the last cycle, the megafauna had mostly survived.  The last one began 18,000 years ago, and it was the most intense of all.  It ended 12,000 years ago.  The ice pack melted, forest advanced, and habitats rapidly changed.  The mammoth tundra fragmented and shrank, which split the herbivore population into isolated groups.

Ward also studied the extinction of dinosaurs.  They roamed the Earth for 160 million years, and then disappeared.  Ward was an early advocate of the notion that the dinosaur mass extinction was sudden, caused by an asteroid strike near Chicxulub, Mexico.  Some say it resulted in a decade of near-freezing temperatures on a planet that was largely tropical.

Throughout the dinosaur era, small mammals also existed — insect eating night creatures.  The extinction of dinosaurs eliminated large animals, and made the age of mammals possible.  If not for the asteroid, humans and elephants would have never evolved.  Mammoth country once ranged from France to Siberia to New York.

Our primate ancestors evolved in the trees.  Their tropical homeland was eventually chilled by an era of glaciation.  It thinned the rainforest, and expanded savannahs, which encouraged the evolution of large mammals, including our hominid ancestors.  Thus, you and I are the children of climate change and asteroids.

Evolution is a process that creates and deletes species.  New species can only emerge when a group becomes isolated, evolves unique traits, and eventually becomes unable to interbreed with their old kin.  Homo sapiens come in many sizes, shapes, and colors, but all belong to the same species, because we can all interbreed.  Ward expects white skinned people to disappear in a few thousand years, because of their increasing vulnerability to skin cancer.

Our cultural myths tell us that humans are continuously getting smarter.  Ward believes that the brains of modern humans are essentially the same as the first Homo sapiens in Africa, 125,000 to 200,000 years ago (but we’ve learned lots of stuff since then).  Once a new species emerges, it changes little thereafter.  Humans are the last species of the hominids, and this has risks.  A gene pool has better odds for long-term survival when it diversifies into multiple species, as the ants have.

Another way for critters to avoid extinction is to become generalists, like humans, rats, and cockroaches, who have adapted to many different ecosystems around the world.  Today, humans live everywhere.  There is no place a group could remain isolated for millennia.  So, there is little chance for a new hominid species to emerge.

Evolution is random, like tossing dice.  The process is influenced by ongoing environmental change, natural selection, and genetic drift (chance genetic changes).  Evolution has no foresight; it can’t anticipate coming changes.  It’s not always progressive.  Greenland ice core data tells us that there have been times when global temperature changed up to 18°F in a few decades.  Many gene pools that work well in one set of conditions will fail to adapt to sudden shifts.

The golden rule of evolution is adapt or die.  Ward doesn’t discuss cultural evolution, which is a million times faster than genetic evolution, and has catapulted humankind onto extremely thin ice, by overloading our tropical primate brains with way too many half-smart ideas.  We are, by far, the world champion resource parasites.  We are hurling countless species into the abyss in our insane impossible quest for perpetual economic growth.

In an extremely quirky twist, Ward celebrates human supremacy at causing mass extinction.  “We are the comet now.  And not only have we won the game of evolution; we control the rules of the game,” he wrote.  “And to this winner, in my view, goes an even greater prize: species immortality.  It is my opinion that no matter where on the board we humans land and no matter what card we draw, we cannot be knocked into extinction.”  Who could disagree?

The book was written 20 years ago, when resource limits and climate change were still dumb ideas among the lunatic fringe — rational people.  Ward is employed in academia, which remains a militant hotbed of radicalized human supremacists.

OK, back to the megafauna.  Doubts are growing about the overkill hypothesis.  Martin claimed a sudden 2,000-year rampage wiped out the megafauna, but this was based on data generated by obsolete dating technology.  Improved dating does not confirm sudden extinction.  Martin claimed the extinctions fanned out in a wave, beginning in Alberta — so kill sites far from there should be more recent.  They aren’t.  We have only discovered a dozen sites where human artifacts are found with mammoth remains.

Dan Fisher has studied of mammoth tusks in Michigan and Ohio.  Tusks have annual rings inside, like tree trunks.  Rings are thin in hungry years.  In female tusks, rings mark each pregnancy, providing a birth rate.  If climate change had killed the mammoths, the rings would indicate malnutrition, but Fisher found that the last mammoths were “fat, fit, and well fed.”

Ward suspects that the mammoths were the victims of hunting.  Unlike bunnies, mammoths were slow to mature, and had low reproduction rates.  If hunters had regularly taken just two percent of the animals each year, the extinction process would have taken 400 years — too slow for each generation of hunters to notice.  Hunting alone could have wiped them out.  Ward thinks that if there had been no hunting, mammoths would probably have survived the warming climate.

In the 1990s, editors adamantly insisted that manuscripts like Ward’s include brilliant solutions and happy endings, because bummer books didn’t sell.  So, his mammoth book ends with a happy visit to the year 3001.  Population was well below its peak of 11 billion.  The U.S. grain belt was a desert.  African survivors were healthy vegetarians with solar panels and pedal-powered transport.  The rainforest was long gone, replaced with endless fields of GMO crops.  Wildlife and livestock had been eliminated by starving hordes.  Happily, the human species survived — hooray!

Compulsory happy endings meant that vital knowledge was deliberately withheld from an entire generation, who are now teachers, reporters, and leaders.  Even today, a “don’t frighten the children” strategy remains common among educators, and young minds are still being infected with a carcinogenic worldview.  Bummer!

Ward, Peter D., The Call of Distant Mammoths, Copernicus, New York, 1997.

The Sixth Extinction

I didn’t rush to read Elizabeth Kolbert’s book, The Sixth Extinction, because I imagined it would be a gloomy expose on the unfortunate consequences of way too much half-baked cleverness — and it was.  But it’s also a fascinating story about the long saga of life on Earth, and the unclever antics of the latest primate species.  It’s an outstanding book.

We have soared away into a fantasy world, where godlike humans spend their lives creating brilliant miracles.  But when observed in a 450 million year timeframe, from this moment when a new mass extinction is gathering momentum, the wonders of progress and technological innovation lose their shine.  Kolbert rips off our virtual reality headsets, and serves us powerful medicine, a feast of provocative news.

The frog people have lived on this sweet planet for 400 million years, but many are now dying, because of a fungus called Bd.  This fungus can live happily in the forest on its own, without an amphibian host, so endangered frogs rescued by scientists cannot be returned to the wild.  The crisis began when humans transported frogs that carried the fungus, but were immune to it.  There was money to be made in the frog business, and so the fungus has spread around the globe.

This is similar to the chestnut blight of a century ago.  Entrepreneurs profitably imported chestnut seedlings from Asia.  The Asian species was immune to the fungus it carried.  American chestnut trees were not immune, and four billion died, almost all of them.  The fungus persists, so replanting is pointless. 

North American bats are dying by the millions from white-nose, caused by fungus that is common in Europe, where bats are immune to it.  It was likely carried across the Atlantic by a tourist who dropped some spores in Howe Caverns, in New York.  By 2013, the die-off had spread to 22 U.S. states and five Canadian provinces. 

Welcome to New Pangaea!  Once upon a time, long before we were born, all seven continents were joined together in a single continent, Pangaea.  Over time, it broke apart, and ecosystems on each continent evolved in a unique way.  In recent centuries, highly mobile humans have moved countless organisms from one ecosystem to another, both deliberately and unintentionally.  The seven continents no longer enjoy the long-term stability provided by isolation.

On another front, many colonies of humans have become obsessed with burning sequestered carbon on an enormous scale.  This is overloading the atmosphere with carbon, which the oceans absorb and convert to carbonic acid.  Carbonic acid is a huge threat to marine life, except for lucky critters, like jellyfish.  The world’s coral reefs are dying.

Tropical rainforests are treasure chests of biological diversity.  Tropical oceans generally are not, because of low levels of nutrients like nitrogen and phosphorus.  Coral reefs are the shining exception.  They provide habitat for thriving ecosystems, home to more than 500,000 species.  This reminded me of beaver ponds, which are also sanctuaries of abundant life. 

Coral polyps and beavers give us excellent examples of reciprocity.  They create relationships that are mutually beneficial for many species.  Reciprocity is a vital idea that most human cultures have forgotten.  Our dominant culture has no respect for the wellbeing of ecosystems.  It has a tradition of displacing or exterminating the indigenous species on the land, and replacing them with unsustainable manmade systems.

Evolution is fascinating.  Rabbits and mice have numerous offspring, because they are vulnerable to predators.  Other species have deflected the predator challenge by evolving to great size, like mammoths, hippos, and rhinos.  Big critters have long lifespans and low birth rates.  This made them highly vulnerable when Homo sapiens moved into the neighborhood. 

Kolbert imagines that the megafauna extinctions were not the result of a reckless orgy of overhunting.  It probably took centuries.  Hunters had no way of knowing how much the mammoth population had gradually dwindled over the generations.  Because they reproduced so slowly, they could have been driven to extinction by nothing more than modest levels of hunting.  An elephant does not reach sexual maturity until its teens, and each pregnancy takes 22 months.  There are never twins.  Deer are still with us, because they reproduce faster.

Sadly, Neanderthals are no longer with us.  They lived in Europe for at least 100,000 years, and during that time, their tool collection barely changed.  They probably never used projectiles.  They have acquired a reputation for being notorious dimwits, because they lived in a stable manner for a very long time, and didn’t rubbish the ecosystem.  Homo sapiens moved into Europe 40,000 years ago.  By 30,000 years ago, the Neanderthals were gone.  The DNA of modern folks, except Africans, contains up to four percent Neanderthal genes.

Homo sapiens has lived in a far more intense manner.  In the last 10,000 years, we’ve turned the planet inside out.  Kolbert wonders if there was a slight shift in our DNA that made us so unstable — a “madness gene.”  I wonder if we’re simply the victims of cultural evolution that hurled us down a terrible path.  If we had been raised in Neanderthal clans, would we be stable, sane, and happy?

Kolbert laments, “The Neanderthals lived in Europe for more than a hundred thousand years and during that period they had no more impact on their surroundings than any other large vertebrate.  There is every reason to believe that if humans had not arrived on the scene, the Neanderthals would be there still, along with the wild horses and wooly rhinos.”

Cultures have an amazing ability to put chains on our mental powers.  Kolbert describes how scientists (and all humans) typically struggle with disruptive information, concepts that bounce off our sacred myths.  Bizarre new ideas, like evolution, extinction, or climate change, are reflexively dismissed as nonsense.  As evidence of reality accumulates, increasing levels of absurd rationalizations must be invented.  Eventually, someone actually acknowledges reality, and a paradigm shift is born. 

For most of my life, human extinction has not been on my radar.  By the end of Kolbert’s book, readers understand that our extinction is more than a remote, theoretical possibility.  What is absolutely certain is that we are pounding the planet to pieces.  Everything is connected, and when one type of tree goes extinct, so do the insects that depend on it, as well as the birds that depend on the insects.  When the coral polyps die, the coral reef ecosystem disintegrates.

The sixth mass extinction is clearly the result of human activities.  The driving forces include the things we consider to be our great achievements — agriculture, civilization, industry, transportation systems.  This is highly disruptive information, and everyone is working like crazy to rationalize our nightmares out of existence.  Luckily, a number of people, like Kolbert, are beginning to acknowledge reality.  Will there be a paradigm shift?  Will we walk away from our great achievements, and spend the next 100,000 years living in balance with the planet?

Kolbert, Elizabeth, The Sixth Extinction: An Unnatural History, Henry Holt and Company, New York, 2014.