Sub-class Placentalia

Order Carnivora

Family Felidae (cats)

Species Acinonyx trumani

Surprisingly, cheetahs were once members of the mammal fauna of North America. Entering over the Bering landbridge sometime in the Pleistocene, the ancestral stock of A. trumani managed to successfully occupy a niche--that of fast predator--on the American Great Plains. Acinonyx trumani was close in size to the extant Old World cheetah (A. jubatus). Weighing about 110 pounds, the American cheetah had slim, elongate limbs, a small head, and lithe body; it probably hunted as does the living cheetah by overtaking its prey at high speed over short distances. Latest occurrence records for this cheetah in North America are in the region of 12,700 years ago.

See also: Kurtén, B., and E. Anderson, 1980. Pleistocene Mammals of North America. Columbia University Press: New York.






 


Sub-class Placentalia

Order Carnivora

Family Felidae (cats)

Species Smilodon fatalis


Charles Knight painting © AMNH

An icon for the late Pleistocene fauna of North America, Smilodon fatalis was about the size of an African lion (Panthera leo). It had enormous canines ("sabers") which protruded inches below its chin line when the jaws were closed. In order to stab its prey, the sabertooth had to open its lower jaw into a 95° gape, so as to clear the points of the sabers. How the sabers were used is still debated.

Great quantities of remains of this species have been recovered in sites in western North America, such as the La Brea Tar Pits in metropolitan Los Angeles. Why this last site should have attracted so many sabertooths is uncertain, although some scientists have suggested that these cats may have principally been scavengers rather than hunters. A few fossil Smilodon bones have marks on them which may have been made by humans, although this is debated. Last records for sabertooths date to 11,000 radiocarbon years before present.


Charles Knight painting © AMNH

Be sure to see a mounted specimen (the real thing!) of this species at the AMNH!

See also: Biknevicius, A., and B. Van Valkenburgh, 1997. The threat behind the smile: incisors and their function in carnivorans. J. Vert. Paleont. 17 (suppl. to no. 3):32A.






 


Sub-class Placentalia

Order Carnivora

Family Ursidae (bears)

Species Arctodus simus

Giant short-faced bears were the largest carnivores in Pleistocene North America. Arctodus simus ranged from Yukon to Mexico; related species occurred in South America. The common name refers to its surprisingly short, broad muzzle, housing widely spaced, dagger-like canines. Compared to brown and black bears (Ursus arctos, and U. americanus, respectively), they were larger in size (reaching 1,500 lb), and sported much longer legs. Although the latter adaptation implies the ability to pursue live prey, it is possible that giant short-faced bears were principally scavengers. The latest dates for North American species indicate that they died out about 11,000 to 12,000 radiocarbon years before present.

See also: Kurtén, B., and E. Anderson, 1980. Pleistocene Mammals of North America. Columbia University Press: New York.