Species that don't get enough publicity #13: Bison

Today’s overlooked species is rather paradoxical; it’s not really overlooked as the genus has become a symbol of an entire continent. People of that continent can recognize one instantly. Empires have risen and fell because of them. Their meat is expensive but delicious. Their herds range over thousands of miles, and only centuries before covered the entire continent in a thick swath. They are the last American megafauna, and they escaped the fate of their neighbors by the skin of their teeth. That’s right, we’re talking about American bison. Yesterday was Bison Day, and I’m going to celebrate our last great mammal before it too is lost to human hunger and short-sightedness.

So, where else to start this post about this classic American emblem than Hebei. The mighty bovid family began their conquest of the world with Eotragus, starting in Central Asia and appearing as east as Thailand and as west as Spain.   Bovids combine complex social behavior with ruminant stomachs, allowing them to exploit the grasslands in ways elephants and rhinos could never attempt. This ability to thrive on grass was perfect for the cooling world of the Miocene, and they grew in size.  8 million years, Buffalo evolved, reaching Africa, Europe and Indonesia.  In India, the genus Bos appears in the Pliocene, and spreads to Britain, Algeria, and Siberia. 

 

However, there is a barrier; the cold steppes of Russia.  While Bos itself can hold on in Europe using warm spells and migration, the harder winters are a challenge. That’s when the wooly cattle evolve. Almost immediately after the evolution of Indian cattle, cold weather varieties develop. One species of Bos, B. mutus, conquers the Tibetan Plateau and  spreads across the steppes. While this species is nearly extinct today, a domestic species succeeds it, ironically created by those driving their wild cousins into extinction. These yaks spread into Mongolia and China in the Pleistocene, and that’s where our friend the Bison first appears.

The oldest Bison is Bison palaeosinensis, discovered by Teilhard De Chardin, a Jesuit theologian and geologist who also discovered the first Homo erectus in China nearby. It seems that we were eating bison as soon as they appeared.  The layers of fur and fat, along with other physiological adaptations, allowed bison to survive the chilly winters of Pleistocene China and spread into Russia. 

Two Russian species evolved: the big grasslands Bison priscus, and the smaller woodlands bison Bison schoetensacki. Together they browsed their way from Europe to the Beringia land bridge. We’ll return to Bison Priscus when we get to Dale Guthrie’s amazing book.  As they reached the Caucasus, the woodland and Steppe bison interbred with the northern Aurochs herds, and the Bos genes influenced the Bison populations to evolve into a new species: the visent. The hybrid outlived the woodland bison, then the aurochs, replacing them genetically. 

Bison started evolving quickly in North America after 250,000 years ago-the Steppe Bison evolved into both giant and slightly smaller species. The Steppe Bison ranged in the Northwest, from Alaska to Idaho. The giant longhorn bison ranged from British Colombia to Guerrero to the Mississippi River to the east, although a small population managed to make it to Florida. This species reached 2.5 meters at the shoulder, 3 meters at the hump, two metric tons in weight, and with a 2-meter horn-span.  The giant size warded off the predatory cats, wolves and bears, and the great horns acted as the ultimate sexual signal.

The ancient bison Bison antiquus, roamed from California (well represented at the La Brea Tar Pits) to Virginia south of the Ice sheets.   For 200,000 the species outnumbered every other megafauna, and while not as big as its giant cousin, was a respectable 2.27 meters at the shoulder and 1.5 metric tons with a meter-long horn-span.  The lions, sabertoothed cats, dire wolves and short-faced bears relied on them as regular prey for their last 200,000 years, and there’s evidence humans hunted them as well

As the ice ages progressed, populations shifted. 30,000 years ago, the giant longhorn went extinct, probably due to the climate promoting smaller animals in times of famine and the arrival of the first humans on the continent, and their smaller cousins outlived them. The ancient bison itself went extinct about 10,000 years ago, along with many other species such as the sloths, camels, horses, and mammoths that shared its habitat and its many giant predators. 

However, this extinction, probably caused by human pressure as new populations arrived in greater weapons and deadlier weapons, did not destroy the genus. Smaller bodied populations were promoted, and they managed to simply outbreed their human predators. For the next 10,000 years, bison held their own against the bow, spear, and javelin in their current species, Bison bison. This species used to range from Alaska to Durango, from the Appalachians to the Great Basin.  While not as big as the past species, at 2 meters at the hump and 1 metric ton for some bulls, they’re the last megafauna.

The past 200 years have been rough. Population booms of the native Americans often led to bison shortages, and eventually the herds began to become managed. It was the 19^th century that proved the most trying time; in the 1820s, the Comanche empire began to decline as wars with Mexico led to overhunting beyond their usual careful management. To make matters worse, the United States had found out the native peoples of the Americans, slowly being pushed west with the bison they hunted, relied much on the animal.  In the 1860s, the war of extermination had began; in order to exterminate the Native Americans and drive the railroads to California’s gold fields, the bison had to be exterminated as well. High caliber rifles combined with greed for land and racial prejudice on the point of genocide, and bison populations plummeted.  From 40 million at the time of the Mexican-Comanche War, to 5 million as the US pressed into Nebraska to conquer the Cheyenne and Lakota, to finally 300 at the turn of the 20^th century. 

Two things saved the bison: a few ranchers, including the legendary James "Scotty" Philip, Michel Pablo, and Charles Goodnight, maintained herds to save this emblem, and a new agenda to establish national parks. Ulysses S Grant’s Yellowstone National Park had a herd back in 1872, and New York’s Police Commissioner Theodore Roosevelt and his cowboy friends manage to successfully protect the park from local ranchers. Roosevelt would later promote the park as President, all too happy to see one last wilderness in his Industrialized Empire.

Ranchers, government agencies, and native American Nations have worked hard this past century to restore the herds. Now bison number almost 400,000 as wild, captive, or zoo animals. It’s a slow process, retarded by mass agriculture, mining and American politics against conservation, but bison cling on where the rest of the Megafauna have passed. Here’s hoping for another 250,000 years of American bison.

 I apologize for this short entry.