【英语时差8,16】群居的剑齿猫（在线收听）

 Social Saber-Toothed Cats What’s more dangerous than meeting one saber toothed cat? Meeting a gang of them. The saber toothed cat, Smilodon fatalis, existed in North and South America until 10,000 years ago. It was lion sized, but with a heavier build and a short tail like a bobcat. Being one of the most preserved species at the La Brea Tar Pits of Los Angeles, Smilodon is most famous for its seven inch long canine teeth, but its behavior remains shrouded in mystery.Did it live alone or in groups? Some scientists suspect Smilodon was a social cat like the lion, coming to the tar pits to feed on animals trapped in the sticky goo. Of course, the big cats were often trapped too. Surprisingly, their fossils contained healed injuries and debilitating arthritis. Was this a sign that old and wounded cats were supported by other group members? Scientists didn’t think so, but weren’t positively sure. So, scientists conducted a unique experiment, comparing the abundance of Smilodon fossils at the tar pits with the number of modern predators responding to playbacks in Africa. The playbacks were recordings of distressed prey animals, mimicking the conditions at the tar pits thousands of years ago. Playbacks attracted lions, hyenas, and jackals, all social predators. Solitary predators were rare visitors. This was an unexpected finding, since there are fewer social predators than solitary ones in the African population. When they compared data, scientists were excited to find that the proportion of social predators attracted to the playbacks in Africa matched the proportion of Smilodon fossils found at the tar pits.This evidence suggested Smilodon lived in groups. It seems, meeting a saber toothed gang may have been the rule, not the exception.