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.

*Also known by the equally darling nickname "Moss Piglets", and by the technically correct, but boring, title of "Tardigrades".

(Via Exoplanetology)


  1. wait wait wait—what was that Aeon Flux episode where beings that look like this contain an amnesia capsule? the brave couple in the episode try to destroy the beings by blasting them into the sun… but Trevor and Aeon mess everything up, as usual.

  2. I’ve read that tardigrades are a form of life where every specimen is identical. That is, every individual tardigrade has the exact same number of cells as any other individual tardigrade.

    1. There are lots of different kinds of water-bears. Within a species, though, they often do have the same number of cells. It turns out that’s not uncommon among the tiniest animals – some nematodes and wheel animals are the same way. By the way, although they don’t quite make it in space, some of those will survive temperatures past liquid nitrogen.

  3. The European Space Agency deliberately killing living creatures.

    Cute living creatures, at that!

    Where is PETA when you need it?

  4. We should strap them to a rocket and send them to the nearest possibly habitable planet! Might as well jump-start a brand new Water Bear-based civilization while we still have the chance.

  5. For how long can they do this? Because if it isn’t 100 years it probably isn’t an effective way for life to travel the stars.

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