Life has a habit of turning up in the most unlikely of places. Geysers, desert cliffs, even heaps of dung are environments that at least a few creatures call home.

Now balls of moss on glaciers are joining this strange list. The clumps, known as glacier mice, have been found to contain miniature ecosystems. And even in freezing temperatures, scientists found, the inhabitants manage to thrive.

In high winds glacier mice, which form when clumps of dust and organic debris develop a layer of moss over time, hop across vast sheets of ice. Because glaciers are in constant, if slow, motion and are frequently blasted by strong winds, these clumps roll around a bit like tumbleweed, or dust bunnies, and the moss ends up growing on all sides.

After years of growth, the clumps look like mouse-size green balls of vegetal fluff, thus their name. Yet in spite of all the information that has been collected about how glacier mice form and get around, their innards remained a mystery.