One tardigrade is smaller than a poppy seed, but is, without a doubt, the world’s toughest animal
It’s commonly known as the water bear, it can live in frozen lakes, boiling hot springs, on the highest mountain or in the deepest sea trenches.
In the desert, tardigrades can survive for ten years without water and NASA recently even took some into space where there are solar winds and no oxygen, but guess what? The tardigrades survived.
There are over 1,000 different species all over the world and in every environment. They originated in freshwater, 530 million years ago, before later migrating to land. Out of water, they prefer a moist habitat, under leaf litter and moss and actually need at least a film of moisture around their bodies to perform normal bodily functions.
When conditions get more punishing, however, tardigrades shut down all but the essential biological processes. This is an extreme form of resting known as cryptobiosis. They enter a dehydrated state that closely resembles death and reduce their metabolic activity to 0.01 per cent of normal levels.
Tardigrades survive by adapting their bodies to the extreme conditions. When there’s no water, they dry out, replacing nearly all their bodily water with a sugar called trehalose. This forms a gel-like substance that suspends and preserves the animal’s cells. When there’s not enough oxygen in the water, their muscles relax to allow in as much oxygen as possible. Below freezing, the tardigrade’s molecules adapt to prevent the formation of ice crystals.
Image from www.flickr.com/photos/stuutje