What Are the Special Features of Sea Otters?

Fur

• With approximately 650,000 hairs per square inch, sea otter fur is thicker than the fur of all other mammals. They spend a lot of time cleaning and maintaining their fur because it is essential for their survival. Unlike other water mammals, sea otters do not have a layer of blubber to insulate them. Instead, they rely on their fur. The underlayer of fur actually traps air to insulate the sea otters from the cold waters in which they live. Because of their luxurious fur, sea otters were hunted almost to extinction. In fact, the Canadian sea otter population was at one point in the 1970s feared to actually be extinct. Now, sea otter populations are slowly increasing, but they face threats, such as from oil spills.

Paws

• Sea otters have four paws, two in the front and two in the back. The front paws are significantly different from the back paws. On their front paws, sea otters have retractable claws similar to those of a cat. These claws help the otter catch food. The back paws, however, are webbed to facilitate swimming and diving.

Diet and Metabolism

• Sea otters have an incredibly varied diet consisting of almost 160 types of food. They predominantly feast on crabs, fish, octopuses, sea urchins, squid, starfish, clams and mussels. In order to get to the fleshy insides of a starfish, a sea otter bites off the tip of a leg and sucks out the meat. When eating clams and mussels, a sea otter will break them open by smashing them against a rock, or by beating them against their chest. In order to stay warm in the frigid waters, sea otters must eat an astonishing quantity of food -- 25 percent of their body weight every day. The average weight of a male California sea otter is 64 lbs., so he must eat 16 lbs. of food every day.

Living in the Water

• Sea otters spend most of the time in the water and rarely come to shore. They are often floating on their backs. In fact, they sleep and eat in this position. A sea otter's nostrils and ears close when the otter dives underneath the water's surface. Unlike all other types of otters, sea otters give birth in the water, typically in the early spring.