Tardigrades

Tardigrades. Here's an obscure phylum of microscopic freshwater critters that can't swim, but stumble around on leaves and detritus. Tardigrade means "slow step," and the Victorian biologist Thomas Huxley dubbed them "water bears," a name that has stuck. They're all aquatic, though a water bear needs no more than a film of water on a bit of moss. Their powers of surviving drought and freezing (down to the temperatures of interstellar space if they're dry enough) are legendary; waterbears have revived from some wetted herbarium moss samples that were well over a hundred years old. I mention them though I've never seen them. Typical water bears are 100 to 500 nanometers long. But the chance of locating my tardigrades was a fine excuse for getting a microscope.