Tardigrades—also known as “water bears” and “moss piglets” — have been around for more than 500 million years.
First discovered in 1773 by Johann August Ephraim Goeze, more than 1,000 tardigrade species are known today, with new ones found nearly every year.
Nearly impossible to see with the naked eye, these tiny, transparent, eight-legged creatures measure between 0.05 mm (0.002 in) and 1.2 mm (0.05 in) long.
Their telescoping mouth, referred to as a pharyngeal apparatus, can dart out and suck the nutrients from whatever they’re trying to eat.
These omnivores often dine on moss and algae, but they’ll also eat other bacteria and microorganisms. They’re even known to resort to cannibalism (eating other members of their species in order to survive).
Speaking of surviving, tardigrades can live just about anywhere, as long as there is a tiny bit of moisture.
Despite their size, they are shockingly tough! Freezing, dehydration and oxygen deprivation pose no threat to them.
And, thanks to a unique protein that protects their DNA, tardigrades can handle 100 times the radiation that a human can!
Much of their ability to survive is due to a special trick they have up their sleeves — they can enter something called a tun state.
In this state, they turn themselves into a little ball, almost like a pill bug or potato bug, and suspend their metabolism.
In other words, they put their lives on hold until more favourable conditions return. It’s kind of like stepping into a cryogenic sleeping chamber from the movies (ask your parents!).