167 



KEY TO MARINE MAMMALS (Cont.) 



14 Color variable, with at least two basic phases; 1) light background 

 with dark spots and blotches and 2) dark or black background with 

 small spots or rings. For positive identification, skull is 

 needed (see Fig. 29): nasal -premaxi 11 ary contact mostly less than 



3 mm; upper premolar teeth of adults mostly set obliquely; shape of 

 posterior margin of jugal in adults mostly angular; bullae angular, 

 not greatly inflated. Virtually the only small seal south of 

 Alaska (except young elephant seals). HARBOR SEAL 



14' Background color pale silvery with darker steel-gray "saddle" on 

 dorsal surface of nose, head, and body; color usually broken by 

 small, fine rings or blotches, superimposed on dappling of oval 

 to oblong spots, brownish gray to black and about 2x1 cm in diameter, 

 whose long axis usually parallels that of body. For positive iden- 

 tification the skull is needed (see Fig. 29): nasal -premaxi 11 ary 

 contact mostly more than 3 mm; upper premolar teeth of adults mostly 

 set straight; shape of posterior margin of jugal in adults mostly 

 rounded; bullae rounded, greatly inflated. LARGHA SEAL 



For subspecific identification of sea otters, characteristics of the skull 

 must be considered: 



15 Coronoid process (highest lobe of lower jaw) not projecting backward, 

 its posterior edge (as viewed from the side) straight or slightly 

 convex; nasal length usually less than 18 mm; skull viewed from 

 above, with notch or suggestion of notch at narrowest part 



(between the eyes ). Color very dark. NORTHERN SEA OTTER 



15' Coronoid process projecting backward, its posterior edge concave; 

 nasal length usually greater than 18 mm; skull without notch at 

 narrowest part, the bones flaring smoothly to the front and back. 

 Color usually medium brown. SOUTHERN SEA OTTER 



16 Baleen present (Fig. 27); teeth absent; mouth slit extends back at 

 least as far as the eyes (as in Fig. 27); blowhole with double 

 opening; each half of the lower jaw curved outward, connected in 

 front by ligaments (thus mobile with respect to each other). 



(BALEEN WHALES) 17 



16' Baleen absent; teeth present, although sometimes hidden in folds of 

 gums and sometimes absent in old individuals; mouth slit does not 

 extend back as far as eyes (as in Fig. 28); blowhole with single 

 opening; each half of lower jaw straight or bent inwards and rigidly 

 connected at the front. (TOOTHED WHALES) 25 



