Water Bears

The Water Bear is in its own phylum of Tardigrada, ranges from 0.1 mm to 1.2 mm in length and is most often found in patches of lichens or moss in nature and the gutters of homes during Autumn. Water bears have no circulatory or respiratory systems, a primitive digestive tract, and eight clawed legs. They feed by inserting one of their two sharp stylets into cells and sucking its contents. When for whatever reason the water bear feels conditions are not best suited for its survival, it places its legs inside its body, literally turns off its metabolism, and replaces all the water in its body with a sugar.

These small creatures are fascinating for their ability to survive under extreme stresses. Certain species survive natural conditions ranging from being under meters of packed ice to the flows from hydrothermal vents in the high-pressure bottoms of oceans. They seem to survive all that science can dish out. Water bears have been kept at one kelvin (almost absolute zero and colder than outer space) for several minutes and been revived, boiled at 125°C and revived, bombarded with radiation 250 times more than enough to kill a mammal and revived, scanned with an electron microscope and revived, and kept dormant for 120 years in their desiccated state and revived with a single drop of water.