In the Shadow of the Sabertooth

Doug Peacock, the grizzly bear expert, lives near the Yellowstone River in Montana.  In 1968, the largest collection of Clovis artifacts was found not far from his home, on the Anzick ranch.  The Clovis culture of Native Americans existed for about 300 years, from 13,100 to 12,800 to years ago — during the era of megafauna extinctions.  Of the 35 genera of large mammals that went extinct in America, half of them vanished in a 500-year period, from 13,200 to 12,700 years ago.

The Clovis culture developed a new and improved design for the flaked stone points used as spearheads.  The long broad sharp points made it much easier to kill large animals, like mammoths and mastodons.  Amazingly, this new technology spread to every corner of North America within just 200 years.  Clovis points are sometimes found close to the remains of extinct animals.  Clovis technology appeared suddenly, and vanished suddenly.

Today, the waters of the Bering Strait separate Siberia from Alaska.  During ice ages, sea levels dropped, and the strait became dry land, called Beringia.  Around 20,000 years ago, the last era of glaciation peaked.  The glaciers made it impossible to travel from Beringia to warmer regions in the south.  Few, if any, humans migrated into America prior to 15,000 years ago.

About 14,700 years ago, the climate changed when the Bøling-Allerød warming period began.  At that time, sea levels were 450 feet (137 m) lower than today.  During the warm period, thawing opened up a corridor to the south, vegetation recovered, and by 13,100 years ago, it became possible to migrate from Beringia to Alberta and northern Montana.

The human immigrants from Siberia did not live at the top of the food chain.  They often had lunch dates with hungry sabertooth cats, lions, dire wolves, American cheetahs, grizzlies, and short-faced bears.  Short-faced bears weighed a ton, and when they stood on their hind legs, were 15 feet tall (4.5 m).  Maybe Clovis points were invented to reduce losses to predators.  Better weapons also made it easier to hunt large animals.

After 1492, the early European explorers were astounded by the incredible abundance of wildlife in the Americas, compared to the battered ecosystems back home.  But what they saw in America was actually a biosphere that was missing many important pieces.  The zenith of American wildlife was prior to 13,000 years ago.

So, the Clovis period began, existed for 300 years, and vanished.  It ended when the frigid Younger Dryas period began, 12,800 years ago.  The Younger Dryas lasted 1,300 years.  When warmer times returned, some clever people began fooling around with plant and animal domestication, which blew the lid off Pandora’s Box.  We’re still living in this warm phase, an unusually long period of climate stability.  We’re long overdue for another ice age, but industrial civilization has seriously botched the planet’s atmosphere, and we’re sliding sideways into an era of ecological helter-skelter.

There are four theories about the megafauna extinctions, and this subject is the source of decades of loud shouting and hair-pulling.  One theory asserts that a comet or asteroid strike filled the atmosphere with dust, causing a very long winter.  Where’s the crater?  There is none, because the impact hit a glacier.  Why did the short-faced bears vanish, but not the other bears?  How did moose, bison, elk, and humans manage to survive?

The disease theory notes that some viral pathogens, like influenza or cowpox, are sometimes able to transfer from one species to another.  Maybe species that migrated from Asia smuggled in some virulent viruses.  But species-to-species transfers are more likely to happen in confined conditions, like barnyards and livestock herds.  During the extinctions, a variety of browsers, grazers, and carnivores disappeared, from an entire continent, in a short stretch of time.

The climate change theory notes that when the Younger Dryas blast freezer moved in 12,800 years ago, the Clovis culture suddenly vanished.  Eventually, “nearly every animal over 220 pounds (100 kg) died off and only animals weighing less than that survived this extinction.  A notable exception was the grizzly, along with modern bison, moose, elk, caribou, musk ox, polar bear, and chunky humans.”  Why hadn’t numerous earlier ice ages caused similar mass extinctions?

Paul Martin was the father of the Pleistocene overkill theory, which asserts, that man, and man alone, was responsible for the unique wave of Late Pleistocene extinctions.  He believed that the American extinctions occurred rapidly, in a “blitzkrieg” of overhunting.  He argued that across many thousands of years, extinction events corresponded to human colonization — in Australia, the Americas, Tasmania, New Zealand, the Caribbean, and so on. 

Hunting clearly played a role, but it’s hard to believe that all of the horses and dire wolves in America were driven to extinction by hunters with spears.  Blitzkrieg seems like too strong a word.  Unlike mice and bunnies, large mammals have low rates of reproduction.  “If hunters remove just 4 or 5 percent of a population of slow-reproducing wildlife, those animals are on a road headed toward extinction.”  The megafauna extinctions could have occurred gradually, over decades and generations, too slowly to raise alarm.

Climate shifts can spur extinctions.  The hills near Peacock’s home are red, because pine beetles are killing the whitebark pines.  The beetles are thriving because warmer winters enable more to survive.  For grizzlies, pine nuts are a dietary staple.  He worries that the bears might be driven to extinction by tiny beetles that benefit from the emissions of consumer society.

Let’s zoom back to the Clovis site discovered near Peacock’s home in 1968.  He didn’t learn about the site until the mid-1990s.  Scientists had hauled away a bunch of artifacts, but didn’t return to perform a thorough excavation.  Peacock was able to encourage additional work at the site, which began in 1999.  This inspired a years-long adventure in learning, which eventually resulted in a book, In the Shadow of the Sabertooth.

The Anzick site was the richest discovery of Clovis artifacts.  Among the findings was the skeleton of a boy, about 18 months old, the only remains of a Clovis human ever found.  It is also the oldest human skeleton found in the Americas.  The results of DNA sequencing were published in 2014.  “The Montana Clovis people are direct ancestors to some 80 percent of all Native North and South Americans living today.”  This line came from Northeastern Asia.  The boy’s genes strongly resemble those of a 24,000 year old skeleton from Lake Baikal in Central Siberia.

“The one unmistakable lesson of the Late Pleistocene extinction is that human activity combined with global warming is a potential, ageless, deadly blueprint for ecological disaster.”  Today, the disaster we’re creating will be of far greater magnitude, and technology will not be able to rescue us.  It’s time to rise up and defend this planet.

For readers who have a comprehensive working knowledge of paleontology, this book might be easy to understand.  It summarizes the highlights of decades of scholarly research, and comments on the major controversies.  General readers (like me) are more likely to struggle with the non-linear presentation.  Be sure to look at the revised edition (2014), not the first edition (2013).  The first edition was printed before Peacock could review, correct, and polish the manuscript, due to a health crisis — and the text was a mess.  The Kindle version is the first edition.

Megafauna



Baz Edmeades (“ed-meedz.”) grew up in South Africa.  His grandfather, Thomas F. Dreyer, was the paleontologist who discovered an unknown species, Homo helmei.  The new species was an immediate predecessor of Homo sapiens, and it lived 239,000 years ago — in Africa!  Europeans, the self-elected master race, naturally assumed that humankind emerged somewhere closer to London.  White folks were shocked to realize that they were (gulp!) Africans.

South Africa’s Kruger National Park is home to megafauna (large animals) that once inhabited vast regions of the world.  Sadly, poachers have been pushing a number of species close to extinction.  This drove Edmeades crazy.  It inspired him to begin research on a book that became Megafauna — First Victims of the Human-caused Extinction.

During the project, he became friends with Paul Martin, who strongly influenced his thinking.  Martin was the father of the Pleistocene overkill hypothesis, which asserted that overhunting was the sole cause for the megafauna extinctions in North and South America.  They occurred after humans crossed into the Americas from Siberia, 15,000 to 20,000 years ago.

Other scholars disagreed.  They blamed climate change, and its effects on vegetation.  But the extinct species had previously survived a number of big climate swings.  Still others blamed disease, a comet strike, or a combination of factors.  The issue is highly complex, and there is currently insufficient evidence to unify the experts, and drive the controversy extinct.

On every continent except Antarctica, there were spasms of megafauna extinctions.  They occurred in different regions, at different times, not in synch with climate swings.  There is real evidence that humans were not innocent bystanders in these murder mysteries.  They likely played a primary role.

In Australia, some say that the species driven to extinction 50,000 years ago were victims of the newly arrived humans.  On the islands of New Zealand, Tasmania, Hawaii, Tonga, Madagascar, the Caribbean, and the Mediterranean, extinctions occurred at different times, following the appearance of humans.

Much earlier, Africa suffered a severe spasm of extinctions, long before Homo sapiens.  The continent was loaded with megafauna 1.8 million years ago, but many were gone by 1.4 million years ago.  There used to be nine species of big cats (three today), nine types of elephants (one today), four hippos (one today).  There were giant antelopes, giant hyenas, giant pigs, giant monkeys, and giant baboons, all gone.  

Some, including Edmeades, blame overhunting.  At the time, our ancestor Homo erectus had been busy, inventing a new and improved toolbox — knives, saws, axes, cleavers.  This was the Acheulian revolution.  They knew how to use fire, and they may have been the first to use the wooden spear.

In North America, when humans arrived, there were at least nine species of big cats, and seven species of elephants.  The biodiversity was incredible — beavers as big as bears, two-ton buffaloes, armadillos the size of VW Beetles.  Until 14,000 years ago, mammoth country ranged from Western Europe to Mexico.  Aurochs ranged from England to Korea, and south to India and North Africa.  Rhinos ranged from Europe to Sumatra.  Under downtown London are the remains of hippos, elephants, giant deer, aurochs, and lions, residents of the thriving rainforests of England. 

Prior to the spear, our ancestors had been similar to baboons and chimps, scavenging lunch from carnivore kills, and bludgeoning small critters like monkeys and lizards.  Over many thousands of years, evolution had gradually made us better hunters.  Changes to our bones and muscles improved our ability to accurately hurl projectiles, and kill from a distance.  Evolution also improved our long distance running skills.  Our ancestors were much slower than antelopes, but we could chase them for hours, until they collapsed from exhaustion.

Before the spear, we acquired new abilities very slowly, by evolving.  At the same time, other species were also busy evolving new abilities for countering our advances, and maintaining the balance.  With our transition to tool making, we began gaining new abilities by inventing them, a far quicker process.  Spears enabled our ancestors to subdue the man-eating predators who kept them from exploding in numbers.  This rubbished the laws of nature.  Imagine rabbits inventing tools that allowed them to overpower foxes.  With spears, we could also kill large game, acquire abundant meat, and feed more bambinos.

Like the trend of population growth, the trend of techno innovation proceeded slowly for ages, until exploding in recent times.  Innovation allowed us to temporarily sneak around the checks and balances of evolution, and discover the painful consequences of violating the laws of nature in a giddy whirlwind of blissful ignorance.  We invented the ability to disrupt the balance of nature.

All wild animals live in the here and now, paying acute attention to the immediate vicinity.  None devote attention to the balance of nature, or to risks that may arise in the future.  If they get food, they eat; if not, they starve.  Amazingly, some tool-making societies eventually developed a sense of foresight.  They practiced enlightened self-restraint, which included taboos on overhunting and overbreeding — never-ending responsibilities.  Foresight was a slippery path, and some groups slid into domestication.  Unfortunately, societies that master self-restraint are helpless sitting ducks when discovered by civilization — a serious and perplexing predicament.

What really captured my attention while reading, was realizing the incredible abundance of huge, beautiful, powerful forms of life that once thrived on Earth.  It’s almost impossible to imagine how spectacularly alive and healthy this planet was in the days before the toolmakers.  Today, it feels like we’re living in desolate ghost towns, nothing but humans.  I can walk alone all night without fear of being eaten.  Our soundtrack is the rumbling, roaring, screeching noise of planet-eating machinery — not wolves, hyenas, elephants, elk — the wild music of a wild land.

And so, here we are.  We have unluckily inherited a treasure chest of predicaments, all getting worse.  Do you think we can somehow find a way to return to ecological harmony by continuing down the path of technology — solar panels, wind turbines, nanotechnology, space exploration, computer-driven cars?

Our closest relatives, the chimps and bonobos, with whom we share 98 percent of our DNA, provide excellent examples of the benefits of living in compliance with the laws of nature.  They’ve lived in the same place for two million years without trashing it.  Humans who study the school of life can survive in tropical forests without tool making, but seven billion can’t.

Cultures die.  The culture of endless growth and insatiable consumption is moving into its twilight years, as resource limits draw the curtains closed.  A muscle-powered future will require a muscle-powered culture.  We could resurrect the unsustainable cultures of centuries past, and repeat their blunders.  Or, we could learn from their mistakes and try something different and better — like rejoining the family of life, and obeying the laws of nature.  Imagine that.  What can we do to move in that direction?

Anyway, Edmeades provides a long and fascinating discourse on megafauna extinctions.  Megafauna is an unfinished work in progress (as of February 2015).  The manuscript has not been copyedited, but the text is well written, easy for general readers to understand.  Edmeades’ deep knowledge of paleontology is obvious.  This is an important document.

Edmeades, Baz, Megafauna — First Victims of the Human-caused Extinction, 2013.  This fascinating manuscript has been withdrawn from its home location (megafauna.com) for updates.  An earlier version is available HERE.

In 2020 and 2021, Edmeades has been working to finish his book.  Current news can be found at:  https://www.facebook.com/MegafaunaDotCom/

In 2013, the Caustic Soda program produced a slightly-serious interview with Edmeades, a 75-minute podcast.