Cute Water Bears Prefer Life on This Planet
I love Mars missions and going to the Moon, and looking for life on Europa and Enceladus. But let’s leave nonhuman earthlings on Earth, where they belong.
I’m talking about the water bear (aka tardigrade), a cute little character who’s less than a millimeter long, has eight legs, and prefers a bed of wet moss to being rocketed into space.
Smithsonian Magazine describes how European researchers sent a group of water bears into orbit to experience the complete vacuum of space for 10 days and were delighted that more than two thirds of those who were shielded from radiation actually survived.
We’re delighted they survived, too. (Ironically, most of them probably didn’t survive whatever happened to them back in a laboratory on Earth.)
Water bears are remarkable in that they can keep going in extreme conditions. According to Smithsonian:
Scientists have found the tiny creatures surviving in boiling hot springs and buried under layers of ice on Himalayan mountaintops. Experiments have shown that they can survive being frozen at -328 degrees Fahrenheit or heated to more than 300 degrees F, are capable of withstanding pressures as powerful as 6000 times that of the atmosphere and can survive radiation doses that are thousands of times stronger than what would be fatal for a human.
Why are they so good at this? Naturalist Mike Shaw explains how they can curl up and dehydrate themselves.
The little water bear is one of few groups of species that are capable of reversibly suspending their metabolism and going into a dehydrated state called cryptobiosis. In this kind of suspended animation, a tardigrade’s metabolism lowers to less than 0.01% of normal, with water content dropping to 1% of normal. … They’ve been found to live virtually everywhere, from the Himalayas (above 20,000 feet), to the deep sea (below 13,000 feet) and from the polar regions to the equator.
Shaw says it’s conceivable that they could have actually come to Earth from elsewhere. (Unlikely, he says, but who knows?)
However they got here, they’re part of the wonder of life on Earth. And if humans want to go explore on Mars, that’s just fine. But let’s leave the water bears where they belong – be that at the top of the Himalayas, the bottom of the Pacific, or on a nice piece of moss in your garden.