Water Bears - The World's Toughest Animal

A little off topic, but still. . . Here's something I found particularly interesting from last month's Washington Post:

James D. Lawrey, a George Mason University biologist, is studying lichens at several National Park Service sites in the Washington area...

Within their small colonies, they harbor a lot of life.

"One gram of moss from the forest floor, a piece about the size of a muffin, would harbor 150,000 protozoa, 132,000 tardigrades [tiny invertebrates], 3,000 springtails, 800 rotifers, 50 nematodes, 400 mites, and 200 larvae," according to Robin W. Kimmerer in "Gathering Moss: A Natural and Cultural History of Mosses." "These numbers tell us something about the astounding quantity of life in a handful of moss."

Interesting. I know what a a larva and protozan is, I think I know what nematodes, mites,, and rotifers are, but what's a tartigrade?

I looked up tartigrades on wikipedia. They are also called Water Bears. They are kind of cute, at least for a microscopic invertebrate. Compare the cuddly Water bear with a mite. I'll take tartigrades any time.

Now here's the thing I really like about tartigrades. They are apparently the World's Toughest Animal. You can shoot them into space, take them to the deepest ocean depths and let them go, deprive them of air, water, and food for years and they don't care. Send them into the core of nuclear reactor. They'll be fine.

From the wiki entry on tardigrades:

1. Tardigrades can survive being heated for a few minutes to 151 °C or being chilled for days at -272.8 °C (almost absolute zero).
2. Radiation— Shown by Raul M. May from the University of Paris, Tardigrades can withstand 5700 grays of x-ray radiation. (Five grays would be fatal to a human).
3. Pressure—They can withstand the extremely low pressure of a vacuum and also very high pressures, many times greater than atmospheric pressure. In theory, they could even survive the vacuum of space, though the possibility of it is slim.

That's one tough cookie.