They have external ears like sea lions, they fold the ears down when they dive for food. Southern sea otters can grow up to four feet long and weight up to 100 pounds. They use tools for opening food. They often use rocks, shellfish or man-made objects to pry their food from rocks or to open it. Sea otters have extremely high metabolism, and eat up to 25 percent of their body weight each day.
Favorite foods are shrimp, clams, crabs, snails, starfish, abalone, and urchins.
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.