Are you sick of coming home to find your goldfish belly-up? Worried that your cat might stray onto the busy road nearby? Do you wish there was a cute, low-maintenance pet capable of surviving pretty much anything you can throw at it?
Look no further than the tardigrades. Also known as ‘water bears’, largely because they look and move like a cross between a bear and a manatee, tardigrades love ambling around in damp, mossy environments. However, their endearing appearance is only one of the reasons tardigrades can win the hearts of those who learn about them. They are also the toughest creatures in the animal kingdom, and they are almost certainly at a park near you.
The phylum Tardigrada contains over 1000 species, which collectively inhabit practically every part of the planet. Some tardigrades have proven capable of surviving the immense pressures of the deep ocean, extreme temperatures ranging from -270 C to 150 C, prolonged dehydration, powerful gamma ray blasts and the ultimate hostile environment: the vacuum of space (for 10 days at a stretch!). They’re long-lived, too – tardigrades have been revived from 120-year-old museum samples of mosses.
Unfortunately, the secrets of the tardigrades are better kept than most other indestructible superheroes we’re familiar with. Tardigrades tend to prepare for extreme conditions by curling up and going into an extreme sort of hibernation in which their metabolism comes to a complete halt. The production of a special type of sugar, called trehalose, helps to protect and maintain the structure of their cells, which is key to being able to ‘resurrect’ again after their conditions improve. However, their development and genes have been poorly studied, so we don’t yet fully understand how they can pull off such amazing feats of resilience.
So why aren’t there tardigrades in the front windows of every pet store? For starters, they’re small. Even the largest specimens are rarely over a millimeter long, so a microscope is a pre-requisite for any aspiring tardigrade owner. Plus, while they’ve got some amazing tricks up their collective sleeves, they’re not the most interactive pets. A tardigrade dancing its way around a little pool of water is entertaining for a while, but it won’t meet you at the door after a long day. Still, if you’re after a pet you can leave in the car on a hot day, or take with you next time you go spacewalking, a tardigrade may just be for you.