Saber-toothed cats hunted on the South American plains

"Up to now, palaeontologists assumed that a predator weighing up to 400 kilograms and with bone structure similar to that of a forest-dwelling cat would have hunted in woodlands," says Hervé Bocherens. It was thought that would make it easier for the animals -- with their canines up to 30 centimeters long -- to find hiding places from which to attack their prey. But Bocherens' study points to a different conclusion. He compared collagen samples from the bones of various ice age predators -- including the saber-toothed cat, the jaguar (Panthera onca), and a species of wild dog (Protocyon) -- with those of their likely prey. The carbon and nitrogen isotopes he found there enable him to draw conclusions about the kind of environment the animals lived in.

The saber-toothed cats did not eat animals which were at home in thickly wooded country. Their chief prey seems to have been a camel-like, steppe-dwelling ungulate known to scientists as Macrauchenia, and two species of giant sloth (Megatherium und Lestodon) -- who, unlike their surviving relatives, lived on the ground and could grow to several tonnes in weight. There could be a further parallel with today's African lions; the bones of several individual saber-toothed tigers were found together and contained similar isotopes, Bocherens says -- "It may be that these predators, too, hunted together in groups."

The saber-toothed cat (Smilodon) evolved in North America and spread to South America with the formation of a stable land bridge between the two continents some three million years ago. It appears that the saber-toothed tigers' fiercest competitors were not other big cats. The study indicates that the jaguar preferred smaller prey, such as rodents and species of horse. But the ice age dog (Protocyon) seems to have shared the saber-tooths' culinary tastes.

Many types of megafauna died out at the end of the ice age, including the saber-toothed cat. Researchers debate the possible influence of climate change and human activity on the extinctions. The Tübingen researchers believe that a damper climate could have led to increased forestation of the steppe -- reducing the saber-toothed tigers' hunting grounds and ultimately causing them to die out.