They're small and cute, and while indeed these creatures are completely harmless, make no mistake - these are some tough 'gummy bears'. Called tardigrades or water bears, these eight-legged invertebrates have evolved to survive in some of the most extreme environments on Earth. Rightfully so, they've been classed by scientists as extremophiles - creatures that are stubborn enough to keep on living even in the most retched environments like the arctic,deserts, hydrothermal vents or other hellish places.
In all, there are some 400 species of tardigrades identified so far, with the biggest one measuring a little over one millimeter, but most of them are really tiny. What's particularly special about them, besides the fact they look like adorable, miniature-sized, translucent bears, is that these fellows are badass even among the badass, recognized for being able to survive in conditions where other extremophiles couldn't ever touch base. In fact, a more accurate description would be to call them polyextremophile since they can withstand extreme temperatures (both scorching hot and numbing cold), radiation, desiccation and.... vacuum of space.
The water bear is able to withstand such extreme conditions by going into a sort of safe-mode, as it dries up into a little barrel called a tun. In this form neither heat, cold or the wretched vacuum of space can't kill it. This is called anhydrobiosis, and in this state, the water bear essentially shuts down its metabolism and can go without food for months. When it does eat, however, it prefers a stable diet of algae.
In fact, researchers at NASA and Italy's University of Modena and Reggio Emilia are currently extensively studying these creatures to see exactly how they can cope to the harsh vacuum of space. Preservation of sperm, seeds, blood, and food is an emerging new disciplines that involves anhydrobiosis and the long-range implications may even include the ability to travel long distances in space. This could occur through suspended metabolism--cryptobiosis--in humans.