New research finds that grease that coats polar bear fur contains a specialized mixture of chemicals that make it resistant to freezing.

Polar bears don’t have to worry about skipping a wash day. The sebum, or natural oil, on the mammals’ fur helps them survive the harsh Arctic weather by making it hard for ice to stick to them, according to a study published Wednesday in the journal Science Advances.

Now, researchers have discovered the bears have another unexpected Arctic adaptation: greasy fur. It’s a trait that, surprisingly, might help us find alternatives to “forever chemicals,” a class of widely used compounds that are linked to a range of health problems in people.

Polar bears need all the help they can get to survive their frosty Arctic environment. One of their biggest survival secrets appears to be greasy hair. The sebum–or hair grease–on their fur makes it very difficult for ice to stick.

Polar bears thrive in the harsh Arctic due to unique adaptations. Scientists discovered their greasy fur prevents ice from sticking, helping them stay warm. A study analyzed the chemical makeup of their hair,