Photo by ngari.norway.

Over at Nothing in Biology Makes Sense!, I’ve written about a new study that tries to disentangle conflicting sources of natural selection to determine whether big herbivores like antelope, zebras, and ostriches have evolved to run because they’re always running away from predators.

An antelope’s frame is under more demands than evading cheetahs—it also needs to travel long distances to follow food availability with the shifting rainy season. In fact, the North American fossil record suggests that big herbivores on that continent evolved long legs for distance running millions of years before there were predators able to chase after them. And then again, not all predators run their prey down; lions, for instance, prefer to pounce from ambush.

To find out whether gazelles are running for their lives, or running for dinner, go read the whole thing.◼