![]() ![]() But, incredibly, if the water dries up, they can shed 97 percent of their own moisture, wither to one-third their normal size and stop metabolizing. ![]() Tardigrades like or, to be more precise, need water. But if, for some reason, their oxygen supply is suddenly lowered, they can blow themselves up like the Stay Puft Marshmallow Man and just hang out in this anoxybiosis state until they can breathe again. The other one is "active," or what we commonly call "life." That's the state in which they crawl around adorably and eat, sleep, dream, wake, have sex, get in fights, etc. These are two of the three states in which tardigrades can exist. But how the #&¡?!! do they do it? In two non-simple words: anoxybiosis and cryptobiosis. Researchers have boiled them alive, tried to crush them with 40,000 kilopascals (5,801 psi) of pressure, attempted to suffocate them with (variously) carbon monoxide, carbon dioxide, nitrogen and sulfur dioxide, and even shot them into space to see if they could endure the intense ultraviolet radiation from the sun (they could and did).Īll this has won them the status of absolutely, hands down, the toughest creatures in existence. They've also been put on ice for nearly two years at -200 Celsius (-328 Fahrenheit) and brought back to life. When thawed out, the little water bears went right back to business as usual. Scientists have frozen tardigrades down to "functional" absolute zero (0.05 kelvins, -272.95 degrees Celsius, -459.31 Fahrenheit) for 20 hours. This means they can survive just about anything we throw at them (or throw them in). What makes water bears really special is that they're extremophiles. So, yes, tardigrades have a phylum to themselves, backward-facing rear legs and are cute in their weird, boneless way, but as we indicated earlier, that's not why they're famous. ROYALTYSTOCKPHOTO/SCIENCE PHOTO LIBRARY/Getty Images That's right, they've got their own phylum, whereas we humans belong to the Chordata phylum, a classification we share with every other vertebrate on Earth, including fish and the aforementioned skin-shedding snakes. The animal kingdom (Animalia) has about 36 phyla in it - one of those is phylum Tardigrada. But they lack frills like a heart, lungs or veins because their body cavity is what's called "open hemocoel," which means that gas and nutrition can move in, out and around efficiently without complex systems. Inside, they've got the basics: a brain, nervous system, esophagus, stomach, intestines and anus. Like snakes or lobsters, tardigrades sport a tough exterior cuticle that they shed and re-grow as they mature. In other words, taken as a whole, tardigrades can be found in just about every environment we've got. There are also aquatic and marine variations, which hang out in both fresh and salt water. At least, that's what the land-roving species of tardigrades does. In a unique formation, their two rear legs face backward, which gives them added agility when climbing ponderously over moss, lichen and fallen leaves. They have short little legs, each one outfitted with a set of claws. However, they're also see-through, which makes an already difficult task even harder. ![]() They're about a hundredth of an inch in length (500 micrometers) and can actually be seen with the naked eye if you have excellent eyesight and the light is just right. Where are they now, those supercilious white-coated demons with their soft, vulnerable flesh and blood? They're the ashes we tread underfoot as we go about ruling this planet in fulfillment of our destiny! Starting with their discovery of us in 1773, they began poking, prodding, dehydrating, freezing, baking alive and generally torturing us in every twisted way imaginable. With all those other lifeforms gone, we've been free to evolve from microscopic, eight-legged, indestructible, panda-like creatures into giant eight-legged, indestructible, panda-like creatures. That's because there aren't any dogs left, metaphorical or otherwise. Who are we? The humans called us tardigrades. Imagine skimming the funereal suburbs, the ruined farms, the dead forests and assuming that nothing could have possibly remained alive in the face of such devastation.īut soon enough you would see us. If you'd been part of an expedition sent by an alien civilization to see whether any life survived the gamma ray, imagine guiding your spacecraft down through the omnipresent storm clouds until you catch sight of the shattered, empty cities with their toppling husks of skyscrapers, their flooded subways, their corpse-strewn sidewalks. Just as the extinction of the dinosaurs helped pave the way for the rise of mammals (and subsequently humans), the gamma ray made way for something else. ![]()
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