Meet the water bear, Earth’s indestructible animal that will outlive us all

14 Jul 2017

A tardigrade, or water bear. Image: 3Dstock/Shutterstock

There are endless ways to end the human race, with gentle changes to our environment enough to push us over the edge. Not the tardigrade, though. It’s here to stay.

There is plenty of research already looking into apocalyptic events on Earth, with humans potentially wiped out by temperature rises, temperature falls, meteorites, super volcanoes and sea rises. But what about our planet’s hardier species?

Cockroaches are notoriously strong, and ants can handle a fair bit of discomfort, too. But what of the tardigrade? Otherwise known as a water bear, these water-dwelling, eight-legged, segmented micro-animals are as close to an indestructible being as we have on Earth.

For example, last year, it emerged that they could survive for up to 30 years, frozen, without food or water, and could even be brought back to functioning life.

They can endure temperature extremes of up to 150 degrees Celsius, the deep sea and even the frozen vacuum of space. The animal can live for up to 60 years, and grow to a maximum size of 0.5mm, best seen under a microscope.

And now, according to a study in England, they win the prize for ‘most likely to survive an apocalypse’.

Bye bye, humans

Researchers from Oxford could find little or no way to eliminate the water bear from Earth, predicting a lifetime of around 10bn years.

This strengthens interest in the hunt for life on other planets, with Dr Rafael Alves Batista, co-author of the paper, wondering what else is out there.

A postdoctoral research associate at the Department of Physics at University of Oxford, Batista’s study looked at three possible life extinction events, and how water bears may handle the effects.

The research established that the only possible way to eliminate all water bears would be to boil away all of the Earth’s oceans, as neither meteorites (too few), nor star supernovae or gamma-ray bursts (both too far away) would get the job done.

“Without our technology protecting us, humans are a very sensitive species,” said Batista, noting that even subtle environmental changes can have a devastating effect on us.

“There are many more resilient species on Earth. Life on this planet can continue long after humans are gone.

“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.

“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?”

Martian law

The trio of Earth-shattering events investigated would spell the end for humans, no question. However, water bears surviving each and every one of them shows just how resilient life is, once it gets a foothold on a planet.

Prof Abraham Loeb, co-author and chair of the Department of Astronomy at Harvard University, suggested that Mars’ history of once having a somewhat habitable environment means that our focus should be on the Red Planet.

With NASA’s ongoing efforts to send humans to Mars, and a series of rovers already pottering about on Martian soil, this makes even more sense.

The potential for life grows even more when we consider the oceans of water predicted on various moons in our solar system, Europa and Enceladus in particular.

“The discovery of extremophiles in such locations would be a significant step forward in bracketing the range of conditions for life to exist on planets around other stars,” said Loeb, with the paper published this week in Scientific Reports.

Gordon Hunt was a journalist with Silicon Republic