Wrestling ninjas – why sabre-toothed predators have massive arms

A cat-like animal explodes from the long grass and leaps onto an antelope. Its huge bulk drags the target to the ground and its muscled forelegs pin it down. With two long sabre-shaped canine teeth, it stabs its victim in the throat, just the once, severing its blood vessels and windpipe. Death comes quickly.

The hunter could be Smilodon, a sabre-toothed cat that lived throughout North and South America, around one or two million years ago.

Or, it could be a nimravid, another group of hunters that looked like cats, but belonged to a separate, closely-related family. Some of them had sabre-teeth too, and they wielded these weapons between 42 and 7 million years ago, well before Smilodon or its relatives did.

Or, it could be Barbourofelis, a member of yet another group of sabre-toothed not-quite-cats, which lived between 16 and 9 million years ago. Its long sabres slipped into long grooves in its lower jaw, which looked like it was about to melt away.