英語(yǔ)聽力：長(zhǎng)毛象王國(guó)—6

Bears have long claws, but they get worn down by the daily grind, moving around and rooting for food. They are just not sharp enough to rip into the bison’s hide.

To solve this puzzle, we need to look to Africa. African buffalo are similar in size to the extinct steppe bison. So what is their foremost predator? The lion. Lions, unlike bears, have their clawssheathed most of the time to keep them razor-sharp. But when they strike, their claws extend to get a good grip on the victim’s hide. This often leaves deep gouges, just like those found on the mummified bison.

And there’s a second clue. The most efficient way to kill large prey is suffocation. Lions typically clamp their jaws around the victims muzzle in a deadly bite. Our Ice Age bison had a set of puncture marks on its snout, around 9 centimeters apart, the blueprint of lion’s bite.

The third and final clue was found embedded in the bison’s hide, a tiny fragment of lion tooth.

So it seems the king of the savannah once roamed the cold expanses of Ice Age America. These long-lost lions of Beringia were close relatives of those we find in Africa today, but they were up to 25% bigger, amongst the largest lions that ever walked the earth.

Thanks to the bison herds and other big game, they could flourish in the freezing north. But the lion’s family tree begins in Africa. So how do they end up here?