The very hungry (and carnivorous) caterpillar

By Maggie Koerth-Baker at 11:01 am Wednesday, Aug 18

At first, you might think the weirdest thing about this little caterpillar is its body—long and skinny, with a patch of legs at the front and a patch at the back, it does a lot of rearing up and strategically falling onto things. That last bit becomes important later.

See, this little Hawaiian caterpillar is a killer.

The Carnivorous Caterpillar is a product of island evolution, which is, itself, a pretty weird phenomenon. For instance, a study published in PLoS Biology in October of 2006 found that mammal populations on islands can change their physical appearance and structure at a rate as much as 3.1 times greater than that of mainland mammals.

Islands breed both unusual caterpillars and fast-evolving mammals thanks to a combination of isolated populations—through which mutations can more easily spread—fierce competition for limited resources, and the odd interactions that happen between species of plants and animals that are all experiencing the same sort of pressures. After all, the ecological niche—what you eat, where you live, who eats you—a species inhabited on the mainland might not exist the same way on an island. And it's likely to change relatively rapidly, along with resources and the spread of useful mutations. Over hundreds or thousands of years, an island species can come to look and act very differently from its mainland cousins.

This video is part of Life Is—A new website that brings together tons of clips from BBC nature documentaries and arranges them in a procrastination-friendly browsing menu. You can search for videos by climate, geography, even predominant color scheme—so a passing fancy for a carnivorous caterpillar could lead you to pig-nosed turtles, Chinese rice fields and whistling rats.