PHYSICAL CHARACTERISTICS 



The sea otter's characteristics include the following: (1) A coat 

 of sparse guard hair and dense insulating fur which protects it 

 from cold as blubber insulates other marine mammals. A blanket 

 of air remains trapped at all times among the fur fibers of the 

 sea otter so that the skin is never touched by the water of its chilly- 

 environment (fig. 1). (2) Flattened hind feet or flippers for pro- 

 pulsion. (3) Retractile claws on the front feet (fig. 2) (but not 

 on the hind feet), the only member of its family so adapted. The 

 forepaws are used to groom the fur, to gather and grasp food, to 

 break the shells of mollusks and crustaceans against a rock held 

 on the chest, and to pass food to the mouth. (4) A loose flap or 

 pouch of skin under each foreleg, extending partially across the 

 chest, is used to hold food organisms after they are gathered from 

 the bottom until they are consumed while the otter floats on its 

 back at the surface. In the wild it never voluntarily consumes 

 food on land. (5) Flattened and rounded molar teeth having no 

 cutting cusps. These are used to crush the shells, external skele- 

 tons, and flesh of food organisms. (6) A horizontally flattened tail 

 aids propulsion. (7) A manner of swimming under water, similar 

 to cetaceans, by means of vertical undulations of the hind flippers 

 and tail. (8) An external ear (fig. 3) that resembles the ear of 

 an otariid or eared seal more than it does the ear of a land carnivore 

 or of its closest relative, the river otter. 



The body of the sea otter is relatively long and heavy, making 

 progress on land clumsy and slow. Although highly adapted to 

 the marine environment, the sea otter is specialized to occupy the 

 narrow zone of shallow water near shore. Apparently it cannot 

 (or at least is not known to) obtain pelagic food where the sea is 

 deep. It does not undertake seasonal migrations. If removed 

 from its natural environment, i.e., water, and kept in a dry pen, 

 it shows great distress, perhaps because it instinctively senses 

 that its fur may become soiled and through eventual wetting 

 cause chilling and death. Also, in captivity when water is not 

 available, heat prostration and death may occur unless environ- 

 mental temperatures are carefully controlled. 



At birth the sea otter is covered with dense brownish fur and 

 long silky yellowish-tipped guard hair. The head is a light buff 



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