Morphological Characteristics Of Sea Otter Enhydra Lutris L. (Carnivora, Mustelidae) Pelage And First Age Moult

Skin samples were taken from the midback and stomach of sea otters from embryos, new-born, one-month pups and adult sea otters up to 8 years old, from the Commander islands. The pale yellow coat of the embryos was shorter and less dense on the stomach than on any other part of the body. Two types of hair, guard hairs and underfur,were determined on the otters’ back. Generally, the fur of newborn and one-month old pups was still developing, and three different kinds of fur were noted - guard hairs, intermediate hairs and underfur. The cuticular scale pattern of juvenile guard hairs was of a mosaic type in the distal portion and lanceolate in the middle. The cuticle of the underfur and intermediate hairs was lanceolate shaped. No significant differences in embryo and new born pup hair parameters were found. Therefore it is assumed that embryo fur pelage consists of two hair-types with the taller and denser fur of older pups belonging to the juvenile generation. Two types of adult hairs were identified, 3-4 guard hairs and two underfur hairs. The cuticle of the guard hairs was mosaic in style at the blade and lanceolate at the base. The cuticular scale of underfur hairs was lanceolate throuhout their length. The juvenile pelage changed at 2 to 5 months of age, beginning at the chest and groin. At six days the moult progressed from the surface of the stomach to the back, ending on the head and the rump. The overall moult covered 80-90 % of the animals’ skin and concluded by the fourteenth day. Juvenile hairs remained on the head and rump until six months of age. Secondary moulting was noted in the animal living in the house after 55-60 days of observation. The new generation of definitive pelage was thinner and longer, and the moult followed the same order as the first moult. We argue that the first adult moult following the juvenile moult is an adaptation to extreme temperatures