The Almost Indestructible Water Bear
BY AWAKE! WRITER IN JAPAN
▪ SEARCH in almost every type of watery habitat around the world—mosses, ice, streambeds, hot springs, lakes, oceans, and maybe your own backyard—and you might chance upon a water bear, one of the hardiest little creatures in all creation. So tiny that it is barely visible, a water bear has a short, four-segmented body covered with a protective cuticle, and it has eight limbs, each ending in a set of claws. Its overall shape and gait resemble those of a lumbering bear, hence its name.
Water bears are tardigrades, meaning “slow walkers.” Hundreds of species are known, and females lay from 1 to 30 eggs at a time. Tens of thousands of these tiny creatures may be found in just a few handfuls of wet sand or soil. A particularly good place to find them is in roof mosses.
Water bears can survive in the most extreme environments. “Specimens kept for eight days in a vacuum, transferred for three days into helium gas at room temperature, and then exposed for several hours to a temperature of -272°C (-458°F) came to life again when they were brought to normal room temperature,” states the Encyclopædia Britannica. They can also survive many hundreds of times the levels of X-ray radiation that would kill a human. And, theoretically at least, they may be capable of surviving even the vacuum of space for a time!
Their secret is their ability to go into a deathlike state during which their metabolism slows to less than 0.01 percent of normal—virtually undetectable! To enter this state, they draw their legs inside their body, replace lost water with a special sugar, and curl into a tiny, wax-covered ball called a tun. When normal, moist conditions return, they become active again within a few minutes to a few hours. In one instance, water bears that were in a state of suspended animation for 100 years were successfully revived!
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