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Watoga Trail Report

Honey Locust fruit with seeds, a favorite food of the mastodon. K. Springer photo

Ken Springer
Watoga Park Foundation

The demise
of the mastodon

This is the story about how a magnificent animal became extinct thousands of years ago and its companion tree that has yet to get the news. It is also about why that matters.

The mysteries of nature are only self-evident when one takes the necessary time to observe the natural world. Likewise, those who possess curiosity about nature are fortunate, because curiosity is often a path to knowledge.

A recent Watoga Trail Report focused solely upon a single tree, a honey locust growing along the banks of the Greenbrier River in Seebert.

As a result of writing the article, I feel that I have gotten to know that tree personally. As such, I now find myself visiting that tree on a regular basis. In doing so, I have learned something new about the stately old tree. Something that, in a poetic sense, is rather sad.

I have good reason to believe that the tree is patiently waiting for an old friend who will never visit again – the mastodon. And the evidence of my assertion is what lies scattered about at the base of the tree unmolested – its large and durable seedpods.

All passing herbivores totally ignore the fruit of the honey locust. * This fact imposes severe limitations on the geographic expansion of the tree’s DNA. By definition, the sweet fruit of the honey locust has been anachronistic since the mastodon’s demise some 11,000 years ago.

Unaware of the mastodon’s extinction, the tree continues to drop its customized fruit under the canopy of the tree, where it remains until rotted away by the elements.

Thomas Jefferson believed that creatures like the saber-toothed cat and the mastodon were still roaming about in the West’s unknown territories. He had hopes that a few of these giants could be captured as specimens.

In 1803, President Jefferson directed the Corps of Discovery, led by Lewis and Clark, to visit an ancient salt lick known today as the Big Bone Lick State Historic Site in northern Kentucky.

Big Bone Lick is a salt spring where the bones of hundreds of ice age creatures, including the masto-don, were found and can still be viewed to this very day.

(Author’s Note: Big Bone Lick was the scene of another historic drama some 50 years earlier. The salt lick was the site of the Shawnee encampment where Mary Draper Ingles, a captured white woman, made her famous escape. Mary made the long journey on foot up the Ohio and New Rivers, returning back to her home in Draper’s Meadow, Virginia.)

Jefferson, like most of the founding fathers, had an obsession with the bones of ice-age megafauna that had been discovered in the 1700s. It is said that he was fond of arranging a collection of mastodon bones in one of the larger rooms at Monticello.

Of course, we now know that the Corps of Discovery did not encounter any living members of the massive ice age creatures, except for bison and elk. The Wooly Mammoth, Mastodon, Saber -Toothed Cats, and Giant Sloths were long gone by the time of the Lewis and Clark expedition.

The peak of the Ice Age was about 20,000 years ago, a time when a 10-thousand-foot thick sheet of ice covered the northern hemisphere. For over two million years, the large mammals lived in a frigid paradise. There was plenty of food for the herbivores and carnivores alike; they flourished and grew large.

Man arrived in North America about 15,000 years ago, just as the planet was starting to warm. ** There is archaeological evidence that humans hunted and consumed mastodons. By 11,000 years ago, the mastodon, like all of the giant ice age mammals, was extinct.

So, was the mastodon hunted into extinction by humans?

Recent research has shown us that hunting the mastodon did play a role in its demise, but not exactly as we may think. 

Most of the ice age megafauna fell prey to a number of stressors as the earth entered into a long period of global warming. The wooly mammoth, for example, had thrived throughout the Pleistocene on the grassy steppes of the northern hemisphere where hundreds of species of browse covered the landscape.

But as the Earth warmed there were dramatic shifts from open grasslands to forests. The mammoth teeth are designed for low browse, not for trees and shrubs, hence the shaggy creature slowly disappeared.

On the other hand, the cupped and ridged teeth of mastodons allowed them to adapt to the new environment, up to a point.

The honey locust was a favorite of the mastodon who became a seed dispersal agent for this particular species of tree. The seedpods of the honey locust were perfect foodstuff for the giant tusked animal; as well, the huge thorns evolved to protect the bark and branches of the tree.

It was a symbiotic relationship in that the tree provided the mastodon with nutrition and the mastodon spread the tree’s DNA far afield.

It was probably a combination of stressors that brought about the extinction of the mastodon. Recent research indicates that tuberculosis may have contributed to the demise of the mastodon. The disease deteriorated the bone structure thereby disabling the creature.

As mentioned earlier, hunting played a large role. But it had more to do with which members of a mastodon herd that the hunters targeted, rather than the act of hunting itself.

Hunters stalked the dominant males because they tended to be solitary and stood off from the group, making them easier targets. Mastodons were killed in several ways, including running them over a cliff or herding them up a box canyon, thereby trapping them.  

The fact that the hunters were singling out the dominant males had an enormous impact on the rest of the herd. Much like what is happening now in Africa where poachers target the dominant male elephants for their tusks.

All hell breaks out when the herd of elephants or mastodons lose their enforced natural order.

In normal herd conditions, the dominant males keep the young bulls in check. When hunters remove the dominant male from the herd, the testosterone-charged juvenile males create chaos.

Their rampages result in uncontrolled fighting between males. The females are often injured in the process, sometimes fatally. Worse, procreation fails to occur with the unwilling females, resulting in a rapid thinning of the herds.

This theory is borne out by many recent archaeological excavations, some here in the Appalachians. Confirming data has been obtained by examining mastodon bones and tusks, revealing information about chronic diseases and acute injuries.

A picture emerges from such research that confirms how multiple stressors, including hunting and climate change, conspired to kill off the mastodon.

The truth is, humans and occasional outsized asteroids share responsibility for many extinctions and near-extinctions. Consider man’s hand in the fate of the Passenger Pigeon and the Dodo. Relentless hunting is blamed for the loss of the passenger pigeons, while a combination of hunting and the introduction of pigs, dog, and rats resulted in the complete extinction of the Dodo in a relatively short time.

As for the honey locust’s seedpods, its dispersal agent of choice, the mastodon, is but a ghost standing beside a tree that keeps giving forth its fruit to no avail.

Do you like guacamole? The tasty avocado, with its large slippery seed, is yet another example of an anachronistic fruit.
The seed is too large for any modern herbivore to eat and disperse, but during the ice age, it was a preferred food source for giant sloths, gomphotheres, and glyptodons, all now extinct.

The avocado would also go extinct without the intervention of man. Think of that the next time you dip a tortilla chip into a delicious bowl of guacamole.

As for me, I have gathered up a hundred or so of the honey locust seeds, scarified them, and will begin planting them on my property. I have effectively undertaken the coveted job of Proxy Seed Distribution Agent for the honey locust.

The job of Proxy Seed Distribution Agent for the avocado tree is also open. If you can swallow an avocado seed whole and pass it through your system intact, the job is yours.

Ken Springer

*Some domesticated ungulates, such as horses and cattle, will consume the honey locust pods, reportedly issuing viable seeds.

** In 2017 scientists found archaeological evidence of human habitation off California’s Coast in what was dry land during the ice age. Although controversial, these sites are estimated to be 130,000 years old. Source: National Geographic, Michael Greshko April 26, 2017.

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