14 



NORTH AMERICAN FAUNA 68 



Figure 7. — Eight sea otters asleep in a kelp bed at Amchitka Island during 

 a midday rest period. In the foreground a large juvenile rests its head on 

 its mother's abdomen. (KWK 55-18-18) 



7. Eyes do not open until age 25-35 days. 



8. Last upper molariform tooth not broadly flattened and greatest width 

 less than V2 inch. 



9. Baculum of adult about 4 inches in length. 



FIELD RECOGNITION OF THE SEXES 



The sex of a living sea otter in the field may be recognized at a 

 reasonable distance if prevailing v^eather conditions offer good 

 light and visibility. The fact that the sea otter habitually rests 

 on its back and floats high in the v^ater facilitates recognition of 

 the sexes. If the sea otter is wet, so that the fur is slick, the penial 

 bulge of the male (fig. 11) and the tv^o abdominal mammae of 

 the female (fig. 12) may be visible v^ith binoculars up to a distance 

 of about 100 yards. When the fur is dry and fluffy, these definitive 

 characters are less distinct but are visible at close range. 



No instance is knov^n of a male otter carrying a pup on its chest 



