Anatomy

• Sea otter have the densest fur of any mammal with more than a million fibers per square inch. This thick, dense fur helps them maintain an internal homeostasis in the frigid Pacific Ocean. 

• They have two layers of fur, the exterior guard fur, which acts as a waterproof barrier, and the interior underlayer which stays completely dry. The interior stays dry because otters are able to trap a layer of air between their skin and underlayer. 

• Sea otters have agile front forepaws great for catching prey. It also enables them to use tools, such as rocks to breaking open tough to eat food like sea urchins, mollusks, or clams. Their paws are extremely strong and have retractable claws to help them grasp things. 

• Right behind their forepaws, on their forearms they have baggy pockets of loose skin they use to store things. This comes in handy to store food for later, or their favorite tools or rocks. 

All otters have SEMI webbed feet suitable for land and water, but sea otters are the only fully aquatic otter species.

• They have FULLY webbed feet.

• To help swim on their backs, the last digit on their feet is the longest. 

Sea otters have many anatomical adaptations on their head to help them thrive in a marine environment.

• Flat skull to help glide through water easier.

• Eyes and ears are small and located towards the top of the head to help with surface swimming. 

• Special valve-like skin in their ears and nose closes when they go underwater to keep water out.