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tardigrade

Bubbling hot springs. Antarctic ice. Deep ocean trenches. The Himalayan peaks. Few organisms can live in any of these places, but the hardy tardigrade can survive them all. These tiny, eight-legged creatures can endure the most brutal conditions: dehydration, freezing, boiling, crushing pressure, and even radiation in outer space. Tardigrades are just about invincible!

Stats

Scientific Name: Milnesium tardigradum
Other Common Names: water bears, moss piglets
Description: tiny aquatic invertebrates
Habitats: anywhere on Earth with moisture, regardless of temperature, air pressure, and other conditions
Diet: fluids from moss, algae, or smaller invertebrates
Size: about 1 mm long
Cool fact: A tardigrade's mouth is rimmed with sharp "teeth" that can pierce the surface of plants or animals.

Story

The "Hidden Life" of Tardigrades
Tardigrades are some of the toughest creatures in the world. What's their secret?

Tardigrades can handle some brutal conditions, but when things get too intense, they enter a state called cryptobiosis, or "hidden life."

When this happens, a tardigrade loses almost all of the water in its body—which actually helps protect its cells from damage.

As this happens, the tardigrade's body systems nearly shut down. It can survive like this for years, until conditions return to normal.

Tardigrades don't age during cryptobiosis, so being in this state can add months or years to their lifespan!

Stumper

Like all organisms, tardigrades need water to breathe, grow, and reproduce. What does a tardigrade do when their environment dries out?

it shrinks into a waxy ball

it dies within hours

it lives off the water stored in its pudgy body

Correct!

The tardigrade curls into a ball and surrounds itself with a waxy film. The dried-out ball—called a tun—can live on for years, then spring back to action when moistened with water again.

Stumper

What do scientists call an organism like the tardigrade that can live in multiple extreme environments?

microextremophage

monoextremophobe

polyextremophile

Correct!

"Phile" is Greek for "love." Extremophiles, or "extreme-lovers," thrive in extreme environments. Add "poly" (meaning "many"), and you get "polyextremophiles"—organisms that can handle multiple extremes at the same time.

Stumper

Pudgy, clawed tardigrades are sometimes called "water bears" and "moss piglets," but these aquatic animals are more closely related to:

crocodiles

lobsters

manatees

Correct!

Tardigrades aren't mammals like manatees or reptiles like crocodiles. They are more closely related to arthropods—a group of invertebrates that includes insects, spiders, and crustaceans like crabs, lobsters, and shrimp.

Fact or Fiction

Tardigrades are rarely found in mild climates of North America and Europe.

Fact

Fiction

Tardigrades live anywhere with a bit of moisture, but they're most common in moss and lichen in temperate climates. If there's moss in your backyard, tardigrades are probably in it!

Fact or Fiction

Scientists know tardigrades can survive in outer space because they have been found on meteorites and other space debris.

Fact

Fiction

Scientists have taken tardigrades into space to test their toughness. In 2007, tardigrades became the first animals to survive direct exposure to the vacuum and UV rays of space.

Fact or Fiction

A tardigrade can withstand pressure as great to the pressure found in the deepest parts of the ocean.

Fact

Fiction

Fact

In fact, tardigrade can handle six times the pressure of the deepest ocean trench. That's 600 times greater than the pressure at sea level!

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