E. lutris Skull Replica measures 5.7 inches. E. lutris Skull Replica is museum quality polyurethane cast. 2-part skull (separate cranium & jaw). Made in USA. Cast from original specimen.

The Sea otter or E. lutris is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean.

Adult sea otters typically weigh between 31 and 99 lb., making them the heaviest members of the weasel family, but among the smallest marine mammals.

Unlike most marine mammals, the sea otter’s primary form of insulation is an exceptionally thick coat of fur, the densest in the animal kingdom. Although it can walk on land, the sea otter or Enhydra lutris lives mostly in the ocean.

The Sea otter inhabits nearshore environments, where it dives to the sea floor to forage. It preys mostly on marine invertebrates such as sea urchins, various molluscs and crustaceans, and some species of fish.

The sea otter or Enhydra lutris use of rocks to dislodge prey and to open shells makes it one of the few mammal species to use tools.

Unlike most other marine mammals, the sea otter has no blubber and relies on its exceptionally thick fur to keep warm. With up to 150,000 strands of hair per square centimetre, its fur is the densest of any animal.

The fur consists of long, waterproof guard hairs and short underfur; the guard hairs keep the dense underfur layer dry. There is an air compartment between the thick fur and the skin where air is trapped and heated by the body.

Cold water is kept completely away from the skin and heat loss is limited.However, a potential disadvantage of this form of insulation is compression of the air layer as the otter dives, thereby reducing the insulating quality of fur at depth when the animal forages.

An adult’s 32 teeth, particularly the molars, are flattened and rounded for crushing rather than cutting food.

Seals and sea otters are the only carnivores with two pairs of lower incisor teeth rather than three. The teeth and bones are sometimes stained purple as a result of ingesting sea urchins.

The Sea otter or E. lutris has a metabolic rate two or three times that of comparatively sized terrestrial mammals. It must eat an estimated 25 to 38% of its own body weight in food each day to burn the calories necessary to counteract the loss of heat due to the cold water environment.

Its digestive efficiency is estimated at 80 to 85%, and food is digested and passed in as little as three hours.