Arctodus simus

Arctodus simus, also known as the giant short-faced bear is an extinct species of bear. The genus Arctodus is known as the short-faced or bulldog bears. A. simus is the largest bear, and more generally, the largest mammalian land carnivore that walked the earth.¹. It was native to prehistoric North America from about 12.5-800 kya.

Taxonomy, classification and evolution

The short-faced bears belonged to a group of bears known as the tremarctine bears or running bears, which are endemic to the New World. The earliest member of the Tremarctinae was Plionarctos, which lived in Texas during the Pliocene Epoch, (2-5 mya). This genus is considered ancestral to Arctodus, as well as to the modern spectacled bear, Tremarctos ornatus. Although the early history of Arctodus simus is poorly known, it evidently became widespread in North America by the Kansan age (about 800 kya).

Range

A. simus was native to North America, where it ranged from the north central plains -- Alaska and Canada -- to central Mexico, and California to Virginia. It was the most common of early North American bears, being most abundant in California. ²

Dietary habits

Analysis on Arctodus bones showed high concentrations of nitrogen-15, a stable nitrogen isotope accumulated by meat-eaters with no evidence of ingestion of vegetation. A. simus was an obligate carnivore, and as an adult would have daily required 16 kg (35 pounds) of flesh to survive.³⁴

One theory of its predatory habits envisions Arctodus simus as a brutish predator that overwhelmed the large mammals of the Pleistocene with its great physical strength. This idea is considered problematic, as Arctodus, though very large, was quite gracile in build. In order to bring down fellow megafauna, this bear would have had to have been a more robust creature, with a denser skeletal structure. Other experts think the long-legged Arctodus was able to run down smaller Pleistocene herbivores such as steppe horses and saiga antelopes in a cheetah-like fashion. However, in this scenario, the bear’s sheer physical mass would be a handicap. Arctodus skeletons do not articulate in a way that would have allowed for quick turns, an ability required of any predator that survives by killing agile prey.⁴ Dr. Paul Matheus, paleontologist at the University of Alaska Fairbanks, determined that Arctodus' moved in a pacing motion like a camel or horse, making it built more for endurance than for great speed.⁴ Arctodus simus, then, was ill-equipped to be an active predator, leading some to conclude that it was a kleptoparasite⁴, using its enormous size to intimidate smaller predators such as dire wolves, Smilodon and American lions from their kills.

Though seen by some as primarily a scavenger, its fearsome natural weapons could have allowed it to attack slow-moving animals such as the Megatherium, according to U.S. National Park Service paleontologist Greg McDonald. Despite being largely herbivorous, Megatherium might also have scavenged on carcasses, possibly as a competitor to Arctodus.⁵

Extinction

The giant short-faced bear became extinct some 12 kya, perhaps partly because some of its large prey died out earlier, and partly also because of competition with the smaller, more omnivorous brown bears that entered North America from Eurasia. Since its demise coincides with the development of the Clovis technology and improved hunting techniques by humans in North America, hunting pressure may also have contributed to its extinction, both directly (human hunting) or indirectly (due to the depletion of other large mammals on which it may have followed for its kills or depended on as prey).

In media

The short-faced bear appears in Zoo Tycoon 2: Extinct Animals as an adoptable animal available at Four Stars Zoo fame.^{citation needed} It also appears in a BBC documentary titled Monsters We Met (also known as Land of Lost Monsters the series shown the animal as an apex predator and competing with early human for food and prey and Wild New World) and the Fox 8's Jurassic Fight Club (episode "Ice Age Monsters"). The show featuring short faced bear as the American lion's rival. A character called Shorty the Bear will appear in Nicktoons: Clash of the Ancients.

Contents

Taxonomy, classification and evolution

Range

Dietary habits

Extinction

In media

See also

References

External links