Short-faced Bear, Arctodus simus

The short-faced bear is an extinct genus of bears that was native to North America during the Pleistoscene era. Other common names include Arctodus and the bulldog bear. There are two subspecies of the short-faced bear, and one of them, Aroctodus simus, is thought to have been the largest terrestrial mammal on earth.

Placed into a group of bears known as running bears or the tremarctine bears, this genus was found in Europe and the Americas. The earliest member of the tremarchtine group, Plionarctos edensis, lived in Tennessee and Indiana during the Miocene Epoch ten million years ago. Along with the modern spectacled bear, this genus is thought to have been an ancestor of the Arctodus genus. Little is known about the history if Arctodus, but it became widespread in North America approximately 800,000 years ago during the Kansan Age. A group of bears related to Arctodus is the Arctotherium genus. The bears from this genus were found in South America. They reached a greater size than Arctodus, but had similar elongated face features. One species in the Archtotherium genus, Arctotherium augustidens, was thought to have been the largest bear ever. The weight of this bear is an estimated 3,500 pounds.

One species in the Arctodus genus, Arctodus simus, is considered one of the largest hunting mammals ever found. It could weigh between 240 pounds through 1,800 pounds and was native to pre-historic North America. Its range stretched from Ikpikpuk River, Alaska to Lowndes County, Mississippi. Research from the type specimen, or example, found in Potter Creek Cave in Shasta County, California shows that male bears from this species from the Yukon may have stood at a height of up to 5.9 feet, thirteen feet if standing on its hind legs. The bears could have weighed up to one thousand pounds.  Larger bears of this species may have been more abundant than previously thought, reaching weights of up to 2,200 pounds. In Riverbluff Cave, Missouri, claw marks have been found reaching up to fifteen feet, re-enforcing the thoughts about the massive size of the short-faced bears.

The second species in the Arctodus genus, Arctodus pristinus, inhabited southern areas such as Texas and eastern areas like New Jersey. It was also found that these short-faced bears lived in southwestern areas such as Aguascalientes, Mexico. They may have had high populations in Florida.

The diet of Arctodus bears is debatable, as older research suggests that they ate only meat and recent research shows they may have eaten plants when available.  Arctodus bones shows a high concentration of nitrogen-15, which is a stable nitrogen isotope commonly accumulated in animals who ate only meat. This shows that Arctodus simus may have eaten up to 35.3 pounds of meat a day. This theory creates an image of a brutish hunter, powerfully overtaking its prey. The physical characteristics, however, show that this method of hunting could not have been possible for Arctodus simus. It had long legs and could have reached speeds of up to forty miles per hour. However, Dr. Paul Matheus , a paleontologist at the University of Alaska Fairbanks,  found that Arctodus would have had a pace similar to camels and horses, showing that their hunting methods would require more endurance than speed. It may have fed on smilodon, American lions, and dire wolves.

The extinction of the Arctodus bear could have happened due to many reasons. The prey of the bears died out before it did, making it possible to assume the likelihood of extinction due to food loss. This possibility is increased because of the fact that Clovis technology was created simultaneously with the bear’s extinction. Human advancement in hunting technology may have caused a decrease in the bear’s food resources. Smaller brown bears that migrated from Eurasia to North America also created competition for the short-faced bear. The short-faced bear became extinct, for whatever reasons, 12,000 years ago.

Image Caption: Skeleton of Arctodus simus, Taken at La Brea Tar Pits. Credit: Riku64/Wikipedia(CC BY-SA 3.0)