There are an estimated 2,100 Southern sea otters. They are a threatened species. Their fur is the thickest of any animals. It has 600,000 to one million hairs per square inch. Humans only have 20,000 on their whole head.
Otters spend lots of time grooming.
They don't have blubber, so they depend on their fur to keep them warm. As they groom their fur to clean it, they force air bubbles next to their skin. The bubbles act as insulation for warmth and provide buoyancy. They have retractable front claws like cats, used for grooming and eating. They can dive up to 120 feet to find food.