34 



NORTH AMERICAN FAUNA 68 



Figure 16. — Horizontal section through skin near surface, midback, adult 

 male sea otter D22-57, anterior at top. The large guard hair in each pelage 

 unit may measure 64 microns in diameter. The fur hairs average 7.2 microns 

 in diameter. At this level the hairs are round to slightly oval in cross 

 section. (VBS 5716) 



hairs, resembles the pattern in all pinnipeds, especially in the fur seals 

 Callorhinus and Arctocephalits. Dead underfur hairs probably (?) accumulate 

 from one year to the next in the bundles of older animals as they do in 

 Callorhinus. The only evidence is that the count in a young sea otter is 43 as 

 compared to 71 and 91 in two adults. This "reluctant shedding," if actually 

 a feature of sea otter pelage, would help to maintain a heat-insulating coat 



