Water bears … in space

Everybody's favorite adorably-monikered, microscopic invertebrate continues to prove that it's also one tough little "bear". Water bears*—long recognized as hardiest animals on Earth—can also, apparently, survive in the vacuum of space, according to a European Space Agency experiment published in the journal Current Biology.

But, before offering the inevitable welcome speeches to our water bear overlords, it's worth noting a couple caveats. First, these water bears weren't just hanging out in open space, wriggling around. Instead, they were in a dehydrated state—a sort-of mega-hibernation that allows water bears to go without water, and appear dead, for years, before being revived. In the video above, you can see a water bear drying out into a little nub, called a tun. But he revives after water floods the petri dish. It was tuns that went to space, not active water bears.

Second, the creatures didn't hold up nearly as well against the Sun, as they did against Space, itself. New Scientist explains:

Ultraviolet radiation, which can damage cellular material and DNA, did take its toll. In one of the two species tested, 68% of specimens that were shielded from higher-energy radiation from the Sun were revived within 30 minutes of being rehydrated. Many of these tardigrades went on to lay eggs that successfully hatched.

But only a handful of animals survived full exposure to the Sun's UV light, which is more than 1000 times stronger in space than on the Earth's surface.

Dried out, the bears can survive a cold vacuum just fine. But only a particularly feisty few made it past the UV exposure. Both pieces of information could prove useful, in the coming Water Bear Imperium.