The world's smallest marine mammal has thicker fur than any other animal on Earth. Instead of having blubber, the sea otter stays warm in cold water habitats because it has more than one million insulating hairs on every square inch of its body, which keep the cold away from its skin. The sea otter also has flaps of loose skin under each forearm that it uses to store food gathered on deep-sea dives, or to stash favorite rocks used to break open tasty finds such as clams, crabs, mollusks, or other shellfish.
- Sea otters can detect faint traces of scent, even underwater. Their sense of smell has been compared to that of a dog. They also use long whiskers to detect prey movement, even in murky water.
- Sea otters can hold their breath for as long as five minutes during a deep sea hunt. Their lung capacity is 2.5 times greater than that of other animals their size.
- Using their forepaws, sea otters capture prey and then use rocks or other found items as tools for cracking open shells. Their webbed feet and rudder-like tails propel them through the water.