THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 47 



Figure 24. — Dentition at birth. The tiny fetal teeth are not erupted from the 

 gums. The canine teeth, a pair of upper incisors, and the first and second 

 pair of lower postcanine teeth are erupted from the gums at birth. 

 Female, captured with mother, Amchitka Island, Alaska, weight 1.5 kg. 

 (3.2 lb.), length 521 mm., umbilical cord attached. (KWK 66-11-2) 



Adult (fig. 21): 



Total on one side, 16; total teeth, 32. 

 Incisors 



At birth the deciduous caniniform incisors (No. 3 pair) are 

 erupted (fig. 22). These are the first functional teeth to be lost, 

 and are replaced after the two central pairs of permanent upper 

 incisors and the two pairs of permanent lower incisors have 

 erupted gingivally at about 2 or 3 months after birth. The four 

 pairs of central incisors are the first permanent teeth. Their ante- 



