What can survive being frozen at just above absolute zero, and sitting in boiling water? What about getting thrown out into space and surviving life in an oxygen-free vacuum with intense solar UV radiation for at least 10 days? It’s the amazing tardigrade! The tardigrade is a tiny, 1 millimeter-long organism that can survive a variety of extreme conditions (conditions that would kill most organisms on Earth), which technically makes it a polyextremophile. Tardigrades (which means “slow-walkers”) are also called waterbears or moss piglets because of their rather adorable appearance and lifestyle; they waddle their barrel-shaped bodies around on eight legs, which have 4 to 8 claws at the ends of each, and spend their days usually sucking liquids out of lichens, mosses, or bacteria.
Although their tiny size is similar to that of unicellular organisms, tardigrades are actually multicellular animals (sometimes having an impressive 40,000 cells). The 1,000-plus species that can be found all over the world today are thought to have their evolutionary origins some 530 million years ago, around when the first trilobites lived, and a few hundred million years before the dinosaurs. The group that they’re most closely related to is the arthropods, which includes insects, spiders, and crustaceans. But they’re clearly rather different from this group.
Tardigrades can also make fascinating lab subjects or even pets. It’s pretty straight-forward to collect, investigate, and grow tardigrades from the wild, where they’re often found on lichen or moss. Alternatively, they can be purchased from online biological suppliers. And only a simple, low-powered microscope is needed to observe them.
So, if you’re looking for a low-maintenance pet that doesn’t take up much space, can tolerate neglect and extreme conditions, and has impressive abilities to show off to friends, consider the amazing tardigrade!
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