It’s an animal that has amazed scientists ever since it was discovered: the tardigrade, or water bear, which can handle everything from boiling water to being frozen for years to even the vacuum of space without dying. They’re one tough critter, and a new study published by scientists in the journal Molecular Cell claims to have figured out how they can survive anything that nature throws at them.

Water bears are very small, invisible to the naked eye. Even when their cells completely dry out, they aren’t dead, which is impossible for most other living things on Earth. But because other creatures like yeast could do this too, scientists had some idea of how they did it, but it didn’t quite add up.

But now they think they understand. The paper states that water bears have special genes that encode for disordered proteins. Basically, when the tardigrade dries out, the cells become filled with these special proteins, turning it into a glassy substance and preventing the molecules from breaking apart, which would kill the animal.

“The big takeaway from our study is that tardigrades have evolved unique genes that allow them to survive drying out,” says Thomas Boothby, the Life Sciences Research Foundation Postdoctoral Fellow at the University of North Carolina, Chapel Hill, and the study’s first author. “In addition, the proteins that these genes encode can be used to protect other biological material–like bacteria, yeast, and certain enzymes–from desiccation.”

“The question has been, ‘If tardigrades aren’t relying on trehelose to survive desiccation, what do they use instead?'” Boothby says.