The first thing you should know is that Water Bears aren’t “mammalian bears” but rather “bears that can live in space”. Yes, they can do it, and are one of the chosen few organisms able to survive in space, not to mention the only complex animal. Despite its minuscule size of approximately 0.1 to 1.5 mm, a water bear is a pretty damn hardy animal.
What are extremophiles, you say? They are organisms that can survive extreme environmental conditions, and are some of the most amazing creatures on this planet. One particular animal extremophile is particularly unique and is a master of survival.
First thing you should know, these bears aren’t really too huggable (unless you’re <1mm tall, which hopefully you’re not or I’ll send my amoebae out to slowly eat you. Water bears aren’t cute and cuddly… they’re rough, tough, and make you look like someone who cries over spilt milk. There are many animals that are extremely resistant to the Earth’s climate, but water bears (Tardigrades) have taken this to an extreme, and can even survive in space for some time, also. Water bears belong to the minor phylum Tardigrada, which has not been studied too carefully and there are about 1,000 discovered species, although the actual species count has been thought to be much more than that, for biologists haven’t delved into their Phylum much. Tardigrades can survive the following in a state of crytobiosis, or total dehydration in a state of no metabolism, whatsoever:
· Exposure to a vacuum and all of the sun’s energy, not just heat, light, and UV rays as we experience it from under Earth’s atmosphere, but also massive amounts of gamma rays and X-rays, too.
· Exposure to 570,000 rads of X-ray radiation, about 500 times the amount of rads it takes to kill a human.
· Survival of cryptobiosis (dry state) for a decade.
· Survival of all of the conditions of space for 10 days! You would die in a matter of seconds! (or less than one)
· Exposure to as high of a pressure as 6,000 Earthen atmospheres, or a pressure as low as a vacuum (already explained).
· Possibly able to survive high concentrations of alcohol.
· Exposure to temperatures of up to 151 degrees Celsius for a few minutes or as low as -200 degrees Celsius for days or-272 degrees Celsius for a couple of minutes. Note that -273.15 degrees Celsius is absolute zero, in which atomic movement slows to a halt and the enigmatic Bose-Einstein condensate forms!
The key to a water bear’s extremophile status is the cryptobiotic stage; because without this, many abilities would be taken away, such as a high immunity to radiation. The Tardigrade is almost dead in the cryptobiotic stage, other than the fact that it can revive itself from this state. Because there is no water in the body of the Tardigrade while in a cryptobiotic state to aid metabolism, the Tardigrade cannot go through any physical changes (from self) while dehydrated.