Sea Otter

Sea Otters

Sea otters forage in relatively shallow coastal waters. They dive to the bottom to catch their prey and surface to eat their food. The dives generally last 1–2 minutes, but they can hold their breath for over 5 minutes. Dive depths range from 5-250 feet. Upon surfacing, the otter will roll onto its back and place the food on their chests. They eat using their front paws and will use tools, such as rocks (which they store under their "arm pit" while diving), to crack open shells. Their main prey species include sea urchins, crabs, clams, mussels, octopus, fish, and other marine invertebrates. Sea otter teeth are adapted for crushing hard-shelled invertebrates such as clams, urchins, and crabs.
Sea otters rely on their high metabolism and their plush coat to keep warm. However, this high metabolism requires them to eat a lot of food. In order to maintain its body weight, a sea otter must eat 25% of its body weight per day.
Sea otters have the densest hair coat of any mammal, with 800,000 to one million hairs per square inch (humans only have 20,000 hairs on their whole head). When sea otters are not foraging, you often see them grooming their fur. They do this to dry their fur and remove salt crystals and excess oil, which fluffs their fur and traps air. Their body heat warms the trapped air and further insulates them. The trapped air provides 4 times as much insulation as the same thickness of fat would provide.