Tough as a Tardigrade

Without water, a human can only survive for about 100 hours. But there’s a creature so resilient that it can go without it for decades. This one millimeter animal can survive both the hottest and coldest environments on Earth, and can even withstand high levels of radiation. This is the tardigrade, and it’s one of the toughest creatures on Earth, even if it does look more like a chubby, eight-legged gummy bear. 

Most organisms need water to survive. Water allows metabolism to occur, which is the process that drives all the biochemical reactions that take place in cells. But creatures like the tardigrade, also known as the water bear, get around this restriction with a process called anhydrobiosis, from the Greek meaning life without water. And however extraordinary, tardigrades aren’t alone. Bacteria, single-celled organisms called archaea, plants, and even other animals can all survive drying up.

For many tardigrades, this requires that they go through something called a tun state. They curl up into a ball, pulling their head and eight legs inside their body and wait until water returns. It’s thought that as water becomes scarce and tardigrades enter their tun state, they start synthesize special molecules, which fill the tardigrade’s cells to replace lost water by forming a matrix. 

Components of the cells that are sensitive to dryness, like DNA, proteins, and membranes, get trapped in this matrix. It’s thought that this keeps these molecules locked in position to stop them from unfolding, breaking apart, or fusing together. Once the organism is rehydrated, the matrix dissolves, leaving behind undamaged, functional cells.

Beyond dryness, tardigrades can also tolerate other extreme stresses: being frozen, heated up past the boiling point of water, high levels of radiation, and even the vacuum of outer space. This has led to some erroneous speculation that tardigrades are extraterrestrial beings.

While that’s fun to think about, scientific evidence places their origin firmly on Earth where they’ve evolved over time. In fact, this earthly evolution has given rise to over 1100 known species of tardigrades and there are probably many others yet to be discovered. And because tardigrades are so hardy, they exist just about everywhere. They live on every continent, including Antarctica. And they’re in diverse biomes including deserts, ice sheets, the sea fresh water, rainforests, and the highest mountain peaks. But you can find tardigrades in the most ordinary places, too, like moss or lichen found in yards, parks, and forests. All you need to find them is a little patience and a microscope.

Scientists are now to trying to find out whether tardigrades use the tun state, their anti-drying technique, to survive other stresses. If we can understand how they, and other creatures, stabilize their sensitive biological molecules, perhaps we could apply this knowledge to help us stabilize vaccines, or to develop stress-tolerant crops that can cope with Earth’s changing climate. 

And by studying how tardigrades survive prolonged exposure to the vacuum of outer space, scientists can generate clues about the environmental limits of life and how to safeguard astronauts. In the process, tardigrades could even help us answer a critical question: could life survive on planets much less hospitable than our own?

From the TED-Ed Lesson Meet the tardigrade, the toughest animal on Earth - Thomas Boothby

Animation by Boniato Studio


Woo, done!

Tardigrades are one of the first successful human-engineered alien species. They come in various shades of red, brown, yellow and blueish-grey, and the tallest recorded one stands at 5′7 [a more common height is around 4 feet]. They are widespread, found all over the galaxy. A peaceful species, they keep to themselves and work at their own pace. They communicate in elaborate sign language, using all of their limbs and feelers, but due to their inability to speak neither vocally or telepathically most other aliens find them frustrating to talk to.

I love all these humans-as-space-orcs posts, and I decided to add my own.

Accept everything as canon so far (humans are insanely resilient death breathers who are utterly reckless with technology, basically fearless, and have a disturbing need to pet everything). Now add tardigrades. Like, an alien sees the human has brought a tardigrade plushy on board, asks what it is, then stares in horror as the human excitedly describes the only creature from Earth more unkilkable than humans using the same tone of voice they’d use to describe a super adorable kitten.

The best part? The human forgets to explain that the plushy isn’t life size.

Justin: Okay, so, I just want to educate real quick everybody about tardigrades, okay? They can survive a few minutes at 304 degrees Fahrenheit. They can survive 30 years at negative 20 degrees Celsius. They can survive a few minutes at negative one thousand degrees Kelvin. They can survive a few days at negative 328 degrees Fahrenheit. They can go without water for 10 years! These are savage beasts, and I’m going to haunt them with the only thing that can stop them: their own fears. What does a tardigrade fear? I can’t fathom it. Because it’s unkillable. It is unfathomable what I’m about to conjure, but it is a Phantasmal Killer. I want to tap into its nightmares, and create- of the one that fuckin’ attacked me, natch- and I will create an illusory manifestation of its deepest fears, visible only to that creature. It must make a Wisdom saving throw, which, if tardigrades are Wisdom-rich, you can go fuck yourself.

Tardigrades aka Water Bears

Here is one of the most alien lifeforms I’ve ever read about… that’s found right here on Earth. These are Tardigrades, or more commonly called ‘water bears’ or ‘moss piglets.’ These peculiar beings look like miniature gummy bears but are really microscopic animals that live in the water, are segmented, and have 8 legs. The name water bear comes from the way that they walk, which resembles that of a lumbering bear. The largest adults may reach lengths of around 1.5 millimetres, whereas the smallest may reach lengths below 0.1 mm. Typically you can find these guys on lichens or mosses, which is where their other name of ‘moss piglet’ stems from.

One of the most interesting aspects of the moss piglet, or water bear, is the ability it has to survive, and even flourish, in environments that we typically think of as uninhabitable. Some can survive temperatures of close to absolute zero (which is −459 °F, mind you); others can withstand temps as high as 304 °F. Not only that, they can take 1,000 times more radiation than other animals, and can go a DECADE without water! Insane!!!Oh, and last but not least, they can survive in space. So watch out, because water bears might take over the universe someday [soon].