They look like pokemons. Well, maybe not that cute. But these little eight-legged creatures are also known as “water bears” because of the lumbering way they move about. But they are small. Tiny in fact. Most are no bigger than 0.3 to 0.5 mm. They are distantly related to insects. They have to moult to grow. But beyond these few basic similarities, there is not much that makes tardigrades like any other living thing on our planet.
Tardigrades were found under ice on mountains,in hot springs, and at the bottom of the ocean. They were known to be able to endure extremes of cold, heat, and pressure and survive. But it wasn’t until they were taken up in a rocket and exposed to the vacuum and radiation of outer space that it became evident they were possibly the most resilient creatures on the planet.
Tardigrades have the ability to “hibernate” when there is little or no water available. But this is not hibernation like a bear in the winter. These periods of hibernation can last as long as ten years. And tardigrades have been found to have a radiation-resistant protein in their DNA that allows them to be exposed to much more cosmic rays than other animals and survive. I used to think cockroaches were tough.
But most tardigrades are found in quiet lakes and ponds, in puddles, on walls or roofs where there is moisture present. In fact chances are that you may have ingested a tardigrade or two at some time in your life when you ate a salad. But don’t worry, as tough as they are, tardigrades cannot survive the digestive juices in your stomach.
One of the more interesting things found by investigating tardigrades, is that their radiation-resistant DNA can be used to increase the radiation resistance of other animals, possibly including humans.This might one day be helpful in space travel. But I think tardigrades might be most useful when man one day decides to live on Mars. Tough, radiation-resistant tardigrades would be good candidates for the first wave of invasion of the Red Planet.