169 



KEY TO MARINE MAMMALS (Cont.) 



20' Flippers with smooth rear edges and not more than one-fifth the total 

 length; longitudinal grooves on belly and throat fine and narrow 

 (1-4 cm) numbering over 40; dorsal fin thin, slender, usually smooth; 

 head without knobs. 21 



21 Ventral grooves end before navel; one ridge on head, from blowholes 



forward. 22 



21 ' Ventral grooves extend to or beyond navel ; one or three ridges on 



head. 23 



22 Ventral grooves number 50-70, longest ones often end between flippers; 

 yellowish baleen, < 21 cm long, with 15-25 yellowish-white bristles 

 per cm, 300-325 plates per side; large white patch on dorsal surface 



of flipper. MINKE WHALE 



22' Ventral grooves number 38-56, longest ones end posterior to flippers 

 though well before navel; baleen<78 cm long, grayish-black with 

 35-60 fine grayish-white bristles per cm (some anterior plates may 

 be partly white), 318-340 plates per side. SEI WHALE 



23 Three prominent ridges on head: one from the blowholes forward, with 

 another on each side; 40-50 ventral grooves; 250-300 slate-gray 



baleen plates with 15-35 gray bristles per cm. BRYDE'S WHALE 



23' Only one prominent ridge on head (blue whale has faint lateral ridges) 

 from blowholes forward; 55-100 ventral grooves; over 310 baleen plates 

 per side. 24 



24 Head broad and U-shaped, as viewed from above; dorsal fin less than 

 33 cm tall, usually triangular, and set. very far back toward tail; 

 baleen all black with 10-30 black bristles per cm, plates extremely 

 broad relative to length, about 318-328 plates per side. 



BLUE WHALE 



24' Head broad at back of mouth slit but sharply pointed at snout; dorsal 

 fin to 61 cm high, curved slightly to moderately backward, and located 

 slightly more than one- third forward from tail to snout; one-fifth to 

 one-third of baleen on right front ivory to yellowish-white, remainder 

 grayish streaked with yellowish-white, plates have 10-15 gray or white 

 bristles per cm and are narrow relative to length, about 356-365 

 plates per side. FIN WHALE 



