Homotherium
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Homotherium serum |
Homotherium is a machairodontine saber-toothed cat genus that lived approximately 3 million to 10,000 years ago in North America, Eurasia and Africa. In Africa, it was possibly a swift predator of antelope and buffalo. It could have also brought down early humans. It first became extinct in Africa some 1.5 million years ago. In Eurasia it survived until about 30,000 years ago (Jelle Reumer et al., 2003). The last scimitar cat survived in North America until 10,000 years ago.
Both Homotherium serum (American scimitar cat) and Homotherium ultimum (Asian scimitar cat) from China, as well as Homotherium latidens from Europe, were derived from the Late Pliocene - Early Pleistocene (about 2 Ma) scimitar cat (Homotherium crenatidens) a widespread Holarctic species. It, in turn, was derived from Machairodus.
Some of the physical characteristics of Homotherium are unusual for a large cat. It had an elongated neck which made positioning the head for biting more precise and effective. Incisors and lower canines formed a powerful puncturing and gripping device. Among living cats, only the tiger (Panthera tigris) has such large incisors, which aid in lifting and carrying prey. The skull had a well-developed crest, where muscles were attached to power the lower jaw. This jaw had down-turned forward flanges to protect the scimitars. Its large canine teeth were crenulated and designed for slashing rather than purely stabbing.
The limb proportions of Homotherium gave it a hyena-like appearance: The forelegs were elongated, while the hind quarters were rather squat with feet perhaps partially plantigrade, causing the back to slope towards the short tail. Features of the hindlimbs indicate that this cat was moderately capable of leaping. The pelvic region, including the sacral vertebrae, were bear-like, as was the short tail composed of 13 vertebrae — about half the number in long-tailed cats. Such features suggest ambushing of prey and short chases. The short cap of the ulna indicates Homotherium was adept at climbing.
The unusually large, square nasal opening, like that of the cheetah (Acinonyx jubatus), presumably allowed quicker oxygen intake, which aided in rapid running and in cooling the brain. As in the cheetah, too, the brain's visual cortex was large and complex, emphasizing the scimitar cat's ability to see well and function in the day, rather than the night, as in most cats.
The best known species of Homotherium is Homotherium serum from North America. Its saber-like canine teeth were shorter than those of Smilodon; however, the scimitar cat's teeth were serrated on both sides, unlike those of Smilodon. It was about the height and weight of a modern lion and was built to run quickly, possibly as fast as 96 km/h (60 miles/h). This predator probably hunted in packs, carrying away the large animals it brought down. One cave in Texas contained the remains of over 30 individuals, which were discovered along with the remains of between 300 and 400 juvenile mammoths (Rawn-Schatzinger 1992). The two images on this page show one of the Homotherium serum skeletons found in Texas.
The worldwide association of Homotherium species with proboscideans (elephants and mastodons) and rhino remains, mainly those of juveniles, suggests that Homotherium preyed selectively on these tough-skinned animals.
In North America fossil remains of Homotherium are less abundant than those of its contemporary Smilodon. For the most part it probably inhabited higher latitudes and altitudes, and therefore was likely to be well adapted to the colder conditions of the mammoth steppe environment.
[edit] References
Reumer, JWF, L Rook, K Van Der Borg, K Post, D Mol, J De Vos (2003) Late Pleistocene survival of the saber-toothed cat Homotherium in northwestern Europe, Journal Of Vertebrate Paleontology
Rawn-Schatzinger, V. (1992) The scimitar cat Homotherium serum Cope, Illinois State Mus., Report of Investigations 47: 1-80.
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