At first glance the sloth might not look all that amazing, aside from being amazingly cute, anyway. But the way they’ve adapted to their environment is pretty incredible. Because they live in trees and eat a low-calorie diet based almost entirely off of leaves, they can’t go running around expending energy all the time. In fact, they lower their body temperatures to keep their metabolism slow, and they only go down to the ground about once a week in order to go to the bathroom. Aside from being chronically constipated (it would seem, anyway), the sloth is so lazy they often go a year or more without attempting to mate. No wonder they have one of the seven deadly sins named after them – or is it the other way around?