Otters, beavers and other semiaquatic mammals keep clean underwater, thanks to their flexible fur

Otters and other semiaquatic mammals can keep clean even in dirty water. AP Photo/Kirsty Wigglesworth

Underwater surfaces can get grimy as they accumulate dirt, algae and bacteria, a process scientists call “fouling.” But furry mammals like beavers and otters that spend most of their lives wet manage to avoid getting their fur slimy. These anti-fouling abilities come, in part, from one of fur’s unique properties — that each hair can bend and flex as an animal moves.

Fouling on boats and machinery can be a big problem, and scientists are searching for ways to prevent it.