Last week I introduced you to a man who hangs out in blocks of ice and swims among icebergs in his trunks just for kicks. Today you’ll meet the bear who thinks he’s a sissy.
Alright, technically it’s not a “bear.” It’s a water bear, or a tardigrade: a tiny, segmented animal between .1 and 1.5 mm in length that probably lives in your backyard. Its common name comes from its slow, plodding gait and comically corpulent appearance under a microscope. Tardigrades live in just about all of the harshest conditions on Earth, from the high Himalayas to sweltering deserts, in both deep sea and fresh water, even on city streets. They can withstand temperatures over 150°C (302°F), or as low as -270°C (-454°F). That’s just above absolute zero! The tardigrade would probably be called “the superman of the animal kingdom” except that it’s immune to kryptonite too.
When tardigrades find themselves in inhospitable conditions they are able to go dormant, expel all water from their bodies and completely halt metabolism. This state is called cryptobiosis. Effectively it’s akin to death, but simply give a cryptobiotic tardigrade some water and it will revive as a fully functional, walking, respiring, reproducing water bear as if nothing had happened. Some dried up specimens found on museum exhibits are claimed to have been revived after 124 years, though I admit that claim is quite apocryphal.
To learn about potential boons to space travel and life in extreme conditions, several space programs, including the Italian Space Agency, have taken tardigrades aboard their shuttles. No, they weren’t being tested on whether they could handle G-forces and excessive amounts of Tang. I’m talking about really extreme conditions: outer space, man! For 12 days the little guys just floated in orbit (inside a container with “air” holes). They had no protection from the vacuum, frigid cold, or DNA smashing radiation of space. Upon return to Earth, most of the 3,000 individuals revived and even went on to reproduce.
All of this is mind-boggling, but the radiation part is particularly so. I’ve seen the way radiation can devastate genetic material in lab. Just a couple hundred kJ/m2 of UV light can wipe out a plate of bacteria by destroying its DNA. Somehow these tardigrades overcame long-term exposure to 7000 kJ/m2 and scoffed at it. Either they can somehow resist genetic damage or repair it really, really well.
|Modified from wired.com|