Chubby, resilient tardigrades — arguably the cutest of all microscopic life — can survive punishing temperature extremes, exposure to the vacuum of space and even being shot out of a gun.
But there’s one thing tardigrades can’t do: see in color.
Tardigrades are related to arthropods (invertebrates with segmented bodies and exoskeletons), and arthropods can see colors because of light-sensitive proteins called opsins, which play a role in vision and circadian rhythms. Tardigrades have opsins too, but little was known about what they do, so scientists recently conducted genetic analysis in two species of tardigrades, to discover how opsins affected sight in these rotund little moss piglets.