Sea otters live in the cold Northern Pacific waters from California to Japan. They have very thick fur, usually brown or straw in color, short legs with claws on the front feet for gripping food and webbed hind feet to propel them through the water. Sea otters can swim up to 1.5km per hour on the surface of the water and up to 8km per hour beneath the surface.
Sea Otter (Enhydra lutris) Facts
Sea otters are the world’s smallest marine mammal, and unlike other marine mammals, they don’t have a thick layer of blubber under their skin. Instead they have thick fur with up to 1 million hairs per square inch of their body. They are covered in two different layers, an undercoat and a layer of guard hairs. This traps air close to the skin keeping the sea otter warm. Oil in the water and other pollutants reduces the fur’s efficacy and sea otters can die from hypothermia as a result.
Sea otter habitats once ranged from Mexico to Alaska but now most sea otters are found in the coastal waters of Alaska, California, Japan and Russia. Sea otters favor areas with kelp, as they like to wrap themselves up in kelp when they rest to prevent from floating away. Current taxonomy of the sea otter is:
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Carnivora
- Genus: Enhydra
- Species: E. lutris
Sea Otter Behavior and Sexual Reproduction
The sea otter is relatively social, and while some may live alone, often females will group with pups and males will group with other males. The sea otter spends most of its life at sea and is considered a little clumsy on land.
Sea otters can breed at any time of the year but pups are usually born during the warmer months. Females are around 4 to 5 years of age when they have their first pup, and gestation lasts between 4 and 5 months. A single pup is born every 1-3 years. At birth, pups weigh between 3-5lb but females will grow to between 16-27kg (35-60lb) and adult males weigh up to 40kg (90lb), though Alaskan sea otters are usually larger and weigh up to 45kg (100lb).
Pups will stay with their mothers until they are 8 months old and the females will spend a lot of time grooming and carrying their pups on their chests. Pups learn to swim at 4 weeks but their fur traps too much air so the pups are unable to dive underwater. When mothers leave their young to hunt, they will wrap them in kelp and the pups will bob up and down on the water’s surface.
Sea Otter Feeding Behavior
Sea otter diet consists of fish, crabs, abalone, mollusks and sea urchins. They have been known to dive to depths of up to 97m searching for food. Once their prey is caught, the sea otter places its catch into the loose skin folds around its armpit, then returns to the surface. Food is placed on the chest as the sea otter floats on its back to eat. Sea otters use their strong teeth and claws to prise open shells, however, they are also known to use tools such as stones to break open tough shells.
Once hunted for its fur, almost to extinction, the sea otter was given protection in 1911. With only around 100,000 worldwide, the sea otter is endangered. Pollution and oil spills are currently the biggest threats to sea otters, destroying their habitats and wiping out resident populations.
References: The Marine Mammal Center and IUCN Red List
Roberta Goli - Roberta has a Bachelor of Science Degree (Zoology), has worked with animals for over 10 years and enjoys writing short stories and flash ...
