Some of us are homebodies, but olms take it to a new level. These cave-dwelling salamanders may stay within the same little patch of ground for years on end.

“They are hanging around, doing almost nothing,” says Gergely Balázs at Eötvös Loránd University in Budapest, Hungary.

Olms are salamanders that live in European caves . They have adapted to life in total darkness: their skin is pale and their eyes don’t develop, leaving them blind. They …