Meet the creature that will outlast us all - the tardigrade

A tardigrade.
A tardigrade. Photo credit: Getty

Long after humans are dead and every other animal has also been wiped out, there's one creature which will keep kicking along like nothing's happened - the tardigrade.

A new study has found the hardy, tiny creatures will probably survive every catastrophe the universe throws at the Earth - at least until the sun blows up.

"Without our technology protecting us, humans are a very sensitive species," said Oxford University's Dr Rafael Alves Batista, co-author of the study, published in journal Scientific Reports.

"Subtle changes in our environment impact us dramatically. There are many more resilient species on Earth. Life on this planet can continue long after humans are gone."

The tardigrade, also known as the water bear, can survive for up to 30 years without food or water. They're only half a millimetre long, but can survive temperatures up to 150degC, the deep oceans and even outer space - where there's no air.

Since little can kill them, tardigrades live almost as long as humans - 60 years.

They're so hardy, scientists say an asteroid would need to be big enough to completely boil away the world's oceans in order to kill them off - and there are none of those known to be on collision course with Earth.

A supernova - or exploding star - would need to be no further than 0.14 light years away to kill them, but the closest star that isn't our sun is four light years away - 28 times too far.

A powerful gamma ray burst would need to come from no more than 40 light years away, the scientists calculate - but that has virtually zero chance of happening.

Accurate illustration of a tardigrade.
Accurate illustration of a tardigrade. Photo credit: Getty

"To our surprise we found that although nearby supernovae or large asteroid impacts would be catastrophic for people, tardigrades could be unaffected," said co-author Dr David Sloan, also from Oxford University.

"Therefore it seems that life, once it gets going, is hard to wipe out entirely. Huge numbers of species, or even entire genera may become extinct, but life as a whole will go on."

"Tardigrades are as close to indestructible as it gets on Earth, but it is possible that there are other resilient species examples elsewhere in the universe," says Dr Batista.

"In this context there is a real case for looking for life on Mars and in other areas of the solar system in general. If tardigrades are Earth's most resilient species, who knows what else is out there."