It's already been established that they can survive deep in the ocean and in outer space. And according to new research from Japan, tardigrades — also known as water bears — can even survive being frozen solid for decades on end.
CBC Radio science columnist Torah Kachur explains what this means for the so-called "toughest creature on the planet."
What makes 'water bears' so remarkable?
Water bears, tardigrades, moss piglets — whatever you call them, these tiny microanimals (usually small enough to fit on the head of a pin) can live pretty much everywhere. Their favourite spot is on moss, which they feed on. I found one swimming in a sample of pond water that I was exploring in a microscope and I have to say, they're almost cute, with thick bodies, eight tiny legs, and a sucker-style mouth.
You've also probably eaten them. They like to live on lettuce or spinach, and without rigorous scrubbing, you've likely had a water bear for lunch.
But what makes them truly amazing is their survivability. They've been experimented on in space, and found in a huge range of environments on Earth, from tropical rainforests to Antarctica to the deep sea. They can survive extreme heat, extreme cold, and extreme pressure.
What does this latest research tell us about their ability to survive?
It's been previously established that tardigrades can survive being frozen — but now we know they can survive being frozen for an incredibly long time.
Japanese researchers successfully thawed some water bears from moss frozen in Antarctica in 1983 — which means they survived being frozen for more than 30 years.
How do you reanimate something frozen in ice for 30 years?
The researchers thawed a moss sample that had been gathered in Antarctica in 1983, and stored at a temperature of -20 C. The sample was thawed at 3 C for 24 hours, and then placed in a Petri dish with fresh water.
Two adult water bears survived the thawing — although it took about nine days until they were fully functional. So did several eggs which were successfully hatched.
Remarkably, one of the adults and one of the water bears hatched from a frozen egg were able to reproduce successfully, which means there was no significant damage to its DNA in that long freezing period, which would have made it infertile.
What are the broader applications for scientists?
Hopefully a lot. The resistance of tardigrades to all sorts of environmental extremes means they have some biological secrets, and their DNA must be particularly resistant to damage.
One of the main things that happens when we age — or when we get cancer, for example — is that our DNA gets damaged. That, in turn, affects our cells and organs. We have a capacity to repair damage done to our DNA, but possibly not as effectively as some organisms like the water bear.
So they may be able to give us clues as to how we can harness the power of our own genomes to do the same.