Beaver: Fur

: Beavers use an oily secretion called castoreum from their scent glands to groom and waterproof their coats, allowing them to stay dry even while submerged for up to 15 minutes.

Beaver fur was the "gold rush" of the 17th and 18th centuries, fundamentally shaping the geography and economy of North America. beaver fur

The effectiveness of beaver fur as a protective barrier comes from its complex anatomy: : Beavers use an oily secretion called castoreum