Mammals: Is It Better To Be Horny or Brainy?

A still from a YouTube video captures the classic predator-prey faceoff: the comparatively bigger-brained lion against a horned wildebeest. Credit: Wildlife Safari TV. The arms race between prey and predator has been around since the first time one microbe evaded another; it's a never-ending spiral of adaptations to be faster, stronger or better-defended. Now a new study looking at antipredator defenses across 647 species of mammals has found animals seem to have taken a couple different evolutionary paths to avoid being eaten. Each path came with a trade-off, however. According to the paper published today in Proceedings of the Royal Society B: Biological Sciences, mammals evolved antipredator defenses in one of two directions: bigger brains or brawnier armor, be it horns, quills, plating, stinky sprays or grenade launchers (okay, kidding on that last one). We've long known that brains are high-maintenance, or "metabolically expensive" in scientific parlance. That gray matter ...