When you’re a badass tardigrade, you don’t have time to whine and moan about radiation or toxic chemicals. You’ve got a life to live, and with only 10 billion years left until the Sun dies, you don’t want to waste any precious moments worrying about basic survival. Fortunately, tardigrades are able to thrive in even the most extreme environments, and scientists have now figured out why.

Despite measuring less than a millimeter in length, tardigrades – also known as ‘water bears’ or ‘moss piglets’ – are pretty much indestructible. Living in aquatic environments around the world, they have absolutely no stress adapting to the deep sea, high altitude, or sub-zero temperatures. They can also tolerate high levels of ionizing radiation and exposure to all sorts of chemicals that would kill just about any other life form.

It has been known for a while that tardigrade cells are protected by a protein called Dsup, which is short for Damage suppression protein. Previous research has even shown that adding Dsup to human cells allows them to withstand dangerous levels of X-ray radiation without being harmed. Yet until now, scientists had no idea how this immortalising protein worked.

Writing in the journal eLife, a team of researchers from the University of California, San Diego, explain how they used an array of biochemical analysis techniques to investigate the activity of Dsup in tardigrade cells. Their results showed that the protein binds to the genetic material inside each cell, forming a protective barrier around it that prevents it from damage.

Radiation such as X-rays can split water molecules inside cells, forming highly dangerous particles called hydroxyl radicals that damage DNA. Hydroxyl radicals can also make their way into cells that have been exposed to toxic chemicals such as hydrogen peroxide.

Yet the researchers discovered that tardigrade cells are immune to hydroxyl radicals thanks to the Dsup shield that protects their genetic material. They therefore conclude that by harnessing the power of Dsup, it may be possible to engineer other animal cells that can survive under extreme conditions.

"In theory, it seems possible that optimized versions of Dsup could be designed for the protection of DNA in many different types of cells," explained study co-author James Kadonaga in a statement. "Dsup might thus be used in a range of applications, such as cell-based therapies and diagnostic kits in which increased cell survival is beneficial."