THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 31 



animals (mean 8.1 percent) fall within the expected range (rabbit, 

 6.2 percent; dog, 7.2 percent; and horse, 9.7 percent (Dukes, 

 1943) ; and walrus, 8.4 percent (Fay, 1958)). In the fifth animal, 

 the blood constituted nearly one-third of the body weight. This 

 animal, when captured, was sleeping on the beach and behaved 

 in a normal energetic way. I noted, however, that it appeared 

 "fat" and the abdomen was round and firm. I suspected then 

 that it was pregnant, but found later that it was not. 



There was no food in the gastrointestinal tract. In addition to 

 the blood quantity, the only abnormality found were two cysts 

 (congenital? 1.5x1 cm. and 1.5x1.5 cm.) containing clear, yellow- 

 ish fluid, on one kidney. The gross appearance of blood was 

 normal. Why this animal retained such a large amount of fluid is 

 unknown. There was no mistake about the quantity of fluid 

 (table 9). 



Pelage and Skin 



Preliminary descriptive studies of the pelage, skin, and molt 

 have been made. 



PELAGE 



Victor B. Scheffer (Marine Mammal Biological Laboratory, 

 U.S. Fish and Wildlife Service) has made a cursory examination 

 of pelage samples from three sea otters and has kindly offered the 

 following notes (in letter, 13 August 1964). Unless otherwise 

 stated, the notes are based on a sample from the midback of 

 "Pappy," an adult male, specimen D22-57, which died in Seattle 

 Zoo on 16 December and was autopsied on 17 December 1957. 



The pelage is an extremely fine wool or fur with the tips of thinly 

 scattered guard hairs protruding from it. It is light smoky gray near the 

 skin, darkening gradually to smoky brown at the surface of the pile. The 

 larger guard hairs are dark; their tips make a layer about 34 mm. (1.5 in.) 

 from the skin. The smaller guard hairs are more numerous than the larger 

 ones; their tips make a layer about 28 mm. (1.25 in.) from the skin. The 

 under fur hairs are by far the most numerous; their tips make a layer 

 about 23 mm. (1 in.) from the skin. The outer surface of the underfur layer 

 is not distinct; the soft, wavy tips of the fur hairs blend with the tips of 

 the smaller guard hairs (fig. 14). 



The pelage unit consists of: a bundle of many underfur hairs and one 

 guard hair at or near the anterior side of the bundle (fig. 15) ; a sebaceous 

 gland on right and left sides of the bundle, joined at the anterior side; a 

 coiled sweat gland beneath and partly adjacent to the follicles of the bundle; 

 and other minor structures. There is apparently no hair-erecting muscle. 



The guard hairs vary widely in diameter and length, though they fall into 



