The mammal with the densest fur is the sea otter (Enhydra lutris). Their fur is incredibly thick and luxurious, boasting a record-breaking density:
Millions of Hairs: Sea otters have an astounding 100,000 to 400,000 hairs per square centimeter (650,000 to 2.6 million hairs per square inch). This is significantly denser than any other mammal!
Secret Weapon: This dense fur isn't just for show. It acts as a natural insulator, keeping them warm in the frigid waters of the North Pacific Ocean where they live.
Unique Structure: Unlike most mammals, sea otter fur lacks guard hairs, the longer, coarser hairs that typically form the outer layer of fur in many animals. Instead, they have a dense undercoat made up of two fur types:
Grooming Champions: Sea otters spend a significant amount of time grooming their fur to maintain its density and insulating properties. They use their forepaws and teeth to constantly clean, comb, and remove debris from their fur.