Newborn sea otter pups weigh 1-2.3 kg and are totally reliant on maternal care for the first five to eight months of life (Kenyon 1969; Payne and Jameson, 1984; Garshelis et a1., 1984; Wendell et a1., 1984). Young pups are covered with a woolly natal coat that is so buoyant when properly groomed that the pup floats when temporarily left unattended by the female (see Chapter 8, Fig. 8.1). As with adult sea otters, the pups lack a subcutaneous blubber layer and are totally dependent on their fur for thermal insulation in the cold, marine environment.
To maintain the fur’s insulating properties, the female may spend up to 30% of her time grooming the pup while holding it on her chest and abdomen (Payne and Jameson, 1984; Vandevere, 1972). Grooming cleans the fur and may be important in aligning the hairs and stimulating the production of natural oils (sebum) which keep the hair healthy and water resistant (Williams et a1., 1988; Davis et a1., 1988). Beginning at six weeks of age the natal pelage is gradually molted. At twelve weeks the pup has acquired its adult pelage and is capable of grooming itself (Payne and Jameson, 1984).
The pup receives nourishment exclusively from the mother’s milk during the first month after birth. As it grows, the percentage of total food intake represented by milk declines and is replaced with solid food obtained by the mother (Payne and Jameson, 1984). By three months of age, most pups are able to swim and make shallow foraging dives. They are unable to break open hard-shelled prey until five to six months of age. Young sea otters become independent at an age of six to eight months and may weigh 10-20 kg (Payne and Jameson, 1984).
