1. Tool use
Sea otters use rocks and empty shells to feed on marine snails, crabs, sea urchins and mussels. There are only a handful of non-primate species known to use tools, including dolphins and octopuses.
2. Back from the brink
Sea otters were brought close to extinction in the 19th century, widely hunted for their fur. This was stopped by the establishment of the International Fur Seal Treaty in 1911. Populations in Canada and California are now doing well.
3. Guardians of the ecosystem
Sea otters are vital to the health of carbon-absorbing kelp forests. They prey on sea urchins that feed on kelp. In environments where sea otter populations have been reintroduced, tall kelp forests are flourishing.
4. Big appetites
A sea otter can consume up to 11kg of food every day to support its high metabolism – that’s about a quarter of its own body weight! The energy demands of a sea otter mother increases by 17 per cent after giving birth.
5. Fur coat
A sea otter’s pelt is the thickest of any mammal. It is made up of a waterproof top layer and a short underlayer, which can contain as many as one million hairs per square inch. This makes up for its lack of blubber in the cold Pacific water.
6. Dedicated mothers
Sea otters give birth in water. Most females have only one pup at a time. The mother will produce milk, hunt and teach the pup how to dive for food until the youngster is five to eight months old and can fend for itself.
7. Lazy days
While extremely agile, sea otters are slow swimmers. They spend the majority of their lives on their backs, only flipping over onto their fronts when greater speed is required. To swim faster they use their webbed feet for propulsion and undulate their bodies.
8. Making friends
Sea otters are polygynous. While mothers and pups are usually solitary, sea otters can form social groups of up to a few dozen. A group of up to 2,000 sea otters is the largest recorded.