Some freaky stuff about real life alien creatures that can’t die

Colourful graphic of a tardigrade and a rider

This is about water bears – also known as moss piglets because they like moss. They are teeny tiny weirdy creatures that can’t be killed.

I’m writing a post about them because they are worth knowing about, but also when there is a post-apocalyptic Hollywood blockbuster featuring them – or at the very least a passing mention on Doctor Who – you will have read if from me first.

Their proper name is tardigrade. I heard about them from my science geek son, and was so sure he was making it up I googled them. And, unless this is some sneaky online trick (and I wouldn’t put it past him tbh) they are real and so freaky they are actually living on the Moon RIGHT NOW.

A Tardigrade seen under a microscope

A tardigrade – like a caterpillar gone dreadfully wrong

Tardigrades are around 1mm long. They can survive without oxygen. They can survive without water. They can survive under pressure (I don’t mean making a cup of tea to your mother’s exact instructions type of pressure, I mean like six times the depth of Marianas trench).

It gets worse/better. Tardigrades can survive down to one degree Kelvin – that is one degree above absolute zero, which is pretty chilly (-273C) and I don’t think actually exists anywhere anyway, so I don’t know how they know this.

On the opposite end of the scale, they can live when the temperature reaches 150C. Hot enough to cook a baked potato. But not a tardigrade.

There is no way to get rid of a tardigrade. They have been blasted with radiation and come out just fine. They have actually been dried out, sent into outer space, brought back, rehydrated and they just shrugged it off.

Some scientists think that tardigrades survived the five great mass extinctions. (Did you know there were five? Me neither. There’s the meteor that wiped out the dinosaurs and four others apparently*).

Okay, they aren’t actually indestructable – if it didn’t know you were coming, you could squish one easily. But what tardigrades have is an incredible defence mechanism. As long as they know that some shit is about to go on down, like oxygen running out or everything suddenly getting hot, they can batten down the hatches and stay alive for decades.

Graphic of a tardigrade from above

What is scary isn’t the tardigrade but the teeny weeny box person – how long has he been a thing?

It is thought they have the ability to turn off their metabolism for at least 30 years. They do this by drying themselves out almost totally completely, which is impossible to do without dying of course, but there you go.

Boil ’em, bake ’em, irradiate ’em, whatever. Once you chuck a glass of water over them they come back to life with no ill-effects, and – get this – they are the same age as when they dried themselves out.

Obviously, scientists are desperate to find out how they do it. In theory, you could dry out an astronaut, send her into space in a packet – no hunger, muscle wasting, bone collapsing, wasting three years of your life or going crackers with boredom.

When she gets to Mars, she rehydrates like a walking talking Vesta curry and is free to have fun on that barren, miserable planet. (Hmmm, you’d have to have water on Mars on start with, don’t know if they’ve thought of that).

Vesta ready meals

Oh happy memories of Vesta ready meals, the magic powder that transforms into a gourmet feast

But you could also do it to vaccines or blood or organs for transplants, and send them to the other side of the world in an envelope instead of a climate-controlled sealed box on a specially charted plane.

There’s lots of theories as to why the scientist who discovered them called them water bears, and none sound very convincing to me. They don’t look like cute little teddies swimming around. They look like cardboard tubes that have got wet and dried out again, with eight zig-zag legs.

But apparently they are everywhere, living in tiny amounts of water. Forget rats or cockroaches. You are never more than a few inches away from a tardigrade. They are actually on the Moon now, having been sent up on the Israeli Beresheet lunar spacecraft, which crash-landed last month, leaving a tub of dehydrated tardigrades stranded up there. As long as they stay dried out, they will be fine (unless no-one turns up with a glass of water in the next few years, that is).

Theories abound that they aren’t from Earth at all, but arrived on some meteorite. One thing’s for certain – when the big meltdown comes and we evaporate, the Earth won’t be left desolate – it’ll be overrun by creepy little water bears, who have been quietly watching and waiting until they can have the place to themselves at last.

*To save you looking it up, here’s the gen on the four others: When around 75% of the world’s species are wiped out, it counts as a Mass Extinction Event. We know the species have gone because of fossils (or lack of them). But we don’t know the reasons. Theories include a snap ice age, the sea losing loads of oxygen, some incredible eruption blasting CO2 everybloodywhere, sea levels dropping and that massive asteroid.

The amazing graphics of tardigrades are on Flikr here.