“A microscopic gummy bear that refuses to die. Anywhere. Ever.”

Half a millimeter of pure stubbornness, the tardigrade — affectionately called a water bear or moss piglet — is functionally impossible to kill. Boil it, freeze it to near absolute zero, blast it with radiation, or fling it into the vacuum of open space (which scientists actually did), and it simply curls into a dehydrated little raisin called a "tun," pauses its entire metabolism, and waits. Add a drop of water years later and it shrugs back to life to continue its busy schedule of trundling around on eight stubby legs eating moss juice. It has survived all five mass extinctions. It will likely outlast us, the sun, and your gym membership. And it looks, frankly, adorable doing it.

Scientific name

Tardigrada

Size

Smaller than a grain of salt (~0.5 mm).

Habitat

Everywhere with a film of water — moss, soil, deep sea, space.

Diet

Plant cells, algae, and the occasional smaller microbe.

Conservation

DD · Data Deficient

Picnic threat level

Picnic threat: already in your sandwich and unbothered.

Schokraie E. et al. (2012), CC BY 2.5, via Wikimedia Commons · Learn more →