Tardigrade

Tardigrada

(tar-di-grad-a)

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Behold the tiny tardigrade in all of its minuscule majesty! There are a thousand known species of tardigrade in the world, and all of them are so small—measuring only 0.005 to 0.12 centimeters (0.05–1.2 mm)—that you have to use a microscope to see them. They have a barrel-shaped body, a tube-like mouthpart, and four pairs of stubby legs with claws on the ends.

These weird-looking invertebrates don’t need a mate to reproduce, so if they can’t find one, they can still have baby tardigrades. Some females can basically clone themselves, while others are actually hermaphroditic—possessing both sexes—and can fertilize their own eggs.

Where They Live

These astonishing creatures are able to survive in conditions that many of us could never dream of. For example, they can handle truly extreme temperatures, from around −455°F (−270°C), far below freezing, up to the scorching heat of 300°F (150°C). They’ve even survived in outer space by placing their bodies into a dormant state known as cryptobiosis.

Found all around the world, from the Arctic to the Antarctic, tardigrades live in all kinds of environments—oceans, sand, rivers, rain forests, mossy tree trunks. In fact, there may very well be some in your backyard right now!

What They Eat

Their tube-like mouths are filled with sharp teeth that they use to suck the juices from the cells of moss, algae, and bacteria. Sometimes they’ll even feast on fellow tardigrades.

Conservation Status

Not Evaluated

These creatures are so small that it’s impossible to count them or figure out exactly where they live, so people haven’t been able to determine whether they’re threatened or not. Because they’re so tiny and also so tough, they probably don’t have many predators—just spiders, crustaceans, mites, snails, and other tardigrades. Of course, climate change may endanger the tardigrade.

Fun Facts

• Depending on their diet, their colors can range from brown to orange to pink to yellow to green. They can even be transparent!
• They’re also known as moss piglets and water bears.
• One specimen survived over 30 years in its dormant state.
• A tardigrade can usually live between three months and two and a half years.
• These animals are so resilient, they’ve survived five mass extinctions over the past 500 million years.

.005–0.12 cm