Water Bears in Space

Ever hear of an animal that can survive boiling hot springs, being frozen inside a glacier, and even the vacuum of space?

Meet the tardigrade, sometimes also called a “water bear.”

Not only do they exhibit a seemingly supernatural ability to withstand environments that would be instantly fatal to most other forms of life, but they look like cute little bears with (admittedly terrifying) claws.

Let’s talk about tardigrades today.

I mentioned that they’re animals, which might lead you to assume they’re insects, but instead tardigrades have their own phylum Tardigrada. Their size is comparable to that of insects, but that’s where the similarities end.

Unlike insects, tardigrades have four pairs of legs, not six. Their bodies aren’t segmented the way insects are—remember head, abdomen, and thorax? Instead, tardigrades are basically tube-shaped.

Here’s where things get really wild. If water isn’t available, tardigrades can shrink up and enter a state called tun. In this state, their bodies replace water with a glass-like substance that protects their organs and DNA until conditions improve. They can stay in this Han-Solo-like state for decades, waiting for the rain to return!

It’s probably no wonder that astrophysicists are fascinated with tardigrades. Their resilience in extreme environments makes them a model for understanding the possibilities of life on other planets and in space.

During the 2007 European Space Agency's FOTON-M3 mission, tardigrades were exposed to the harsh conditions of outer space for the first time. Remarkably, they not only survived the vacuum of space but also exposure to lethal levels of solar radiation. This extraordinary feat cemented their status as one of the most resilient known life forms.

Tardigrades possess unique proteins that help them to become Han Solo. These tardigrade-specific intrinsically disordered proteins (TDPs) create a protective shield around vital cellular components, a mechanism that scientists are exploring for potential breakthroughs in preserving biological tissues and improving the stability of pharmaceuticals.

Once rehydrated, the tardigrade can resume normal life as if nothing happened.

This remarkable mechanism not only sheds light on the possibilities of life enduring in extreme extraterrestrial environments but also opens up potential applications in medicine and biotechnology. Understanding how tardigrades defy death might one day help us figure out how to use a few of their sneaky tricks ourselves.

Is this the planet of the humans, or the planet of the tardigrades? In terms of biomass, humans have much more. In terms of sheer numbers, there are certainly many more of them than there are of us.

Tardigrades love moss. If you can find a good patch of moss about one square meter, you can find tens of thousands of water bears, or moss piglets (I swear, I did not make this last one up) as they’re adorably referred to.

They can live in the depths of the ocean, in the middle of ice, and near volcanoes.

The evidence in their favor continues to mount.

Do you know of other extremophiles like the tardigrade? What else should people know about moss piglets?