Short-faced bear
The short-faced bear (Arctodus sp.) is an extinct bear genus that inhabited North America during the Pleistocene epoch from about 1.8 Mya until 11,000 years ago. It was the most common tremarctine bear in North America and many of its fossils have been found in the La Brea tar pits in southern California.[1] There are two recognized species: the lesser short-faced bear (Arctodus pristinus) and the giant short-faced bear (Arctodus simus), with the latter considered to be one of the largest known terrestrial mammalian carnivores that has ever existed. It has been hypothesized that their extinction coincides with the Younger Dryas period of global cooling commencing around 10,900 BC.
These species appear to have a disproportionately short snout compared with most modern bears, giving them the name "short-faced." This apparent shortness is an illusion caused by the deep snouts and short nasal bones of tremarctine bears compared with ursine bears; Arctodus has a deeper but not a shorter face than most living bears. This characteristic is also shared by the only living tremarctine bear, the spectacled bear.[2] The scientific name of the genus, Arctodus, derives from Greek, and means "bear tooth".
The short-faced bears belong to a group of bears known as the Tremarctinae, which appeared in North America during the earliest parts of the late Miocene epoch in the form of Plionarctos, a genus considered ancestral to Arctodus. During the Great American Interchange that followed the joining of North and South America, tremarctines invaded South America, leading to the evolution of Arctotherium and the modern spectacled bear (Tremarctos ornatus). Although the early history of Arctodus is poorly known, it evidently became widespread in North America by the Kansan age about 800,000 years ago.
Arctodus simus first appeared during the middle Pleistocene in North America, about 800,000 years ago, ranging from Alaska to Mississippi,[3][4] and it became extinct about 11,600 years ago. Its fossils were first found in the Potter Creek Cave, Shasta County, California.[5] Remains of the giant short-faced bear, along with Paleo-Indian artifacts and the remains of the flat-headed peccary, stag moose, and the giant beaver were found in the Sheriden Cave in Wyandot County, Ohio.[6]
A. simus might have been the largest land-dwelling species of Carnivora that ever lived in North America. A giant short-faced bear skeleton has been found in Indiana, unearthed south of Rochester.[7] It has become well known in scientific circles because it was the most nearly complete skeleton of a giant short-faced bear found in America. The original bones are in the Field Museum of Natural History, Chicago.[7]
Arctodus pristinus inhabited more southerly areas, ranging from northern Texas to New Jersey in the east, Aguascalientes, Mexico[8] to the southwest, and with large concentrations in Florida, the oldest from the Santa Fe River 1 site of Gilchrist County, Florida paleontological sites.
