Tardigrade Tough Enough To Survive 5 Mass Extinctions
If you’re like me, you’ve missed this column. It may have seemed like there would never be a return. Here we are though, returned from our apparent demise, which leads us to one of my favorite animals and today’s subject, the tardigrade, a microscopic animal that has something of a habit of resurrecting from even the harshest of situations.
Strictly speaking, “tardigrade” translates to “slow stepper,” which when combined with their nickname “moss piglets,” provides a radically misleading image for one of the most extreme animals this planet knows how to create. Tardigrades are also known as “water bears” and while that may bring to mind images of furless and finned grizzlies roaming the oceans looking for their next meal, it’s much, much cooler.
Discovered in the 1770s, tardigrades look like a faceless, translucent, Michelin Man on all fours. For clarity, by “faceless,” I mean the majority of their face area is occupied by a telescoping mouth filled with sharp teeth like the Xenomorph from the “Alien” movies. Also, by “all fours,” I mean all eights because a water bear has 8 clawed legs that, like its mouth, it can retract back into its body when it goes into hibernation.
Oh right, tardigrades are fans of going into hibernation whenever the environment isn’t up to snuff. If it’s too cold, too hot, or just not what they were hoping for, tardigrades can go into a hibernation trance for 10 years or more with some reports estimating the upper range at near a century. They accomplish this by dropping their body from 85% to 3% water. All they need is a little rehydration once the environment is better and they can go about their business. Not that the environment has to be too particular for a tardigrade.
While tardigrades are generally found in wet, mossy environments, they have also been found in hot springs, the top of the Himalayas, buried under ice, and at the bottom of the ocean. The pressure alone at the lowest point of the ocean can crush all but our most sophisticated equipment but tardigrades are fine with it. The temperature doesn’t mean much either as water bears can survive anywhere from 300 oF to -400 oF. Keep that in mind next time you’re arguing about the thermostat. There are even reports of tardigrades being frozen for 30 years, unfrozen, and getting back to work because again, they are immortal resurrection machines.
Even radiation only registers as a minor nuisance to tardigrades. By some measurements, tardigrades can survive 1,000 times the radiation of other animals. This resilience is attributed to their 3% water content when in hibernation. So they tested hydrated tardigrades. After the exposure, the water bears started repairing their own D.N.A. of the radiation damage.
In an effort to test the true limits of tardigrades, on more than once occasion, they were even brought up to space. That’s not so terribly remarkable, we’ve done that with monkeys, dogs, even an ill-fated gecko mission from 2014. The difference with the water bear missions is that they were on the outside. Dehydrated tardigrades were exposed to the vacuum, cold, and solar radiation of space for 10 days in low earth orbit, brought back to Earth, and successfully rehydrated. Tardigrades are the first animal we know of to be able to survive unaided in space earning them the additional nickname, “space bears.”
With Earth Day approaching and protections of the natural world being eradicated by folks who wouldn’t know an eagle from an egret, remember the tardigrade. The microscopic water bear that has survived 5 mass extinctions and shows no sign of giving up now. We should all strive to be tardigrade tough.
