Science Snippet: What Are Tartigrades?

Tartigrades are tiny invertebrate animals that are so unusual they have been assigned to a special phylum with no other animals in it. “Tartigrade” literally means “slow walker.” These animals are about as large as the period at the end of this sentence, but under a microscope, they look like sausages with eight stubby legs that move them slowly along through mosses, lichens and leaf litter. What makes them so unusual is that they are virtually indestructible. They are unfazed by temperature up to 302 degrees F or by temperatures as low as minus 328 F. When their habitat dries up, they lose moisture and form dust-like spheres that can be blown about by the wind. When these spheres, called “tuns,” land in a favorable area, the encysted tartigrade soaks up moisture and once again becomes an eight-legged creature, feeding on detritus and other vegetation in their new surroundings. When tartigrades were sent into space to expose them to solar heat, radiation and the vacuum of space, they returned to earth unaffected. In a nuclear war, tartigrades and cockroaches may be among the few survivors. (New Scientist, Sept.-Oct., 2011)