How do tardigrades survive being frozen and dried out?
Meet the tardigrade — a tiny creature smaller than a grain of sand, waddling through moss and pond water on eight stubby legs. It looks like a microscopic bear crossed with a vacuum cleaner, which is why people call it a "water bear." But this little weirdo has a superpower that would make any superhero jealous: it can survive being frozen solid, dried out completely, blasted with radiation, or even shot into space. How does something tinier than a freckle become nearly indestructible?
The secret starts with what a tardigrade does when trouble arrives. Let's say the puddle it lives in starts drying up under the hot sun. Most creatures would panic. The tardigrade does something wild instead: it pulls its eight legs in tight, shrivels up into a dried husk called a "tun," and shuts down completely. Not sleeping — actually stopping. Its heart stops. Its cells stop dividing. It's like hitting pause on a video, except the video is alive.
