Live Tiny, Die Never

Quick announcement first: I’m gearing up for a big science communication conference next week. There will be a lot of cool stuff there, which I’ll be sharing all through the conference on Instagram and Twitter! BUT there won’t be a blog post next week. The next one after this will be the Friday after, April 13.

But in the meantime, I would like to introduce you to a truly bizarre critter. At 1 millimeter in length, this is the smallest creature yet featured on the Wild Focus Project. Behold the weird and wonderful water bear! (Also known as a tardigrade, or moss piglet.)

The future is tardigrade. Image from the Science Photo Library, via Nature.

Tardigrades curl up into a tun (right) to protect themselves from extreme environments. Image from Goldstein Lab.

Tardigrades first appeared on Earth some 500 million years ago, pretty much exactly the same way they are now. They’re prolific, arguably cute, and basically indestructible, so why change? These aquatic 8-legged micro-animals have an amazing set of adaptations that allow them to survive just about anywhere, although most just hang out in patches of moss or swampy areas. But they’ve been found all over the planet, from the peaks of the Himalayas to the depths of the oceans. Their most notable survival trait is their ability to become a tun, a curled up dehydrated ball that keeps them in stasis. When a tardigrade becomes a tun, the metabolism slows down and a sugary substance protects the internal tissues. Some tardigrades live in environments where they have plenty of water, but not enough oxygen – they enter a stretched-out state designed to maximize oxygen intake.

Here are some of the craziest things that tardigrades can survive:

Tardigrades are the only known organisms to be able to survive exposure to space. Image from the TARDIS (Tardigrades In Space) Project, via Team Tardigrades.

  • Temperatures ranging from a roasting 150°C/300°F all the way down to -272°C/-457°F (almost Absolute Zero, when atomic motion stops)
  • Hot springs with dangerous chemicals that would be poisonous to most animals, as well as exposure to strong acids and pure alcohol
  • Decades of dehydration, and possibly over 100 years without water – one researcher claimed that tardigrade tuns from a 120-year-old moss sample came back to life when exposed to water, but the result has never been replicated.
  • Pressures up to 600 megapascals, equivalent to 6000 times higher than normal atmospheric pressure at sea level
  • Direct exposure to X-rays and gamma radiation strong enough to destroy DNA in other organisms.
  • Bombardment by a stream of pure electrons
  • The freaking vacuum of SPACE, with no protection, for more than a week. Humans couldn’t do that for more than about 15 seconds. But tardigrades exposed to space for 10 days survived and some even had viable offspring. WHAT.

No doubt about it – they’ll outlive us all.

Here’s the best part: Tardigrades are everywhere. There are over 1000 different species in just about every environment on the planet. You could collect some moss from your backyard or local park, and probably find some tardigrades if you look carefully. But no need to freak out about it – they’re harmless.

Anyway, here’s a video of a tardigrade having a poo.

Talk to you in a couple weeks!