12. a. Two conspicuous grooves on outer surface of throat forming V-shape pointed forward; notch absent 



or inconspicuous in flukes. (Beaked whale) Go to 13 



b. No conspicuous grooves on outer surface of throat; deep median notch on rear margin of tail 



flukes Go to 18 



13. a. A pair of teeth located at the tip of the lower jaw (erupted only in adult males, concealed in females 



and immature animals) Go to 14 



b. Noteethat the tip of the lower jaw Goto 16 



NOTE: Immature individuals of the species covered in paragraphs 14 and 15 may not be readily identifiable without 

 museum preparation and examination. 



14. a. Two well-developed teeth, erupted or hidden beneath the gum, are compressed so they appear 



elliptical in cross section; body to 16 feet (4.9 m); united portion of the lower jaws* more than one- 

 fourth the length of the entire lower jaw. 



True's beaked whale, p. 77 

 b. Two well-developed teeth substantially less flattened so that they appear more nearly rounded 



in cross section Go to 15 



15. a. Distinct elongated beak; pronounced bulge to forehead; blowhole located in lateral crease behind 



bulge; body to 32 feet (9.8 m); sometimes second pair of teeth behind first in lower jaw. 



Northern bottlenosed whale, p. 67 

 b. No distinct beak; forehead slightly concave in front of blowhole, increasing in concavity with 

 increasing size; body to 23 feet (7.0 m); united portion of lower jaw less than one-fourth the length of 

 the entire lower jaw; head of adult males all white. 



Goosebeaked whale, p. 70 



16. a. A single pair of teeth in the united portion of the lower jaw, at the suture of the mandible (about one- 



third of the way from the tip of the snout to the gape); length to 22 feet (6.7 m); flukes less than one- 

 fifth the body length. 



Antillean beaked whale, p. 78 

 h A single pair of teeth backof united portion of lower jaw; body less than 17 feet (5.2 m) Goto 17 



17. a. Teeth not exceptionally large and located immediately back of united portion of lower jaw. about half 



way from the tip of the snout to the gape. 



North Sea beaked whale, p. 82 

 b. Teeth exceptionally large, located on bony prominences near the corner of the mouth, and oriented 

 backwards; corners of mouth, particularly in adult males, have high-arching contour; flukes to one- 

 sixth or one- fifth of the body length. 



Dense-beaked whale, p. 80 



18. a. Rostrum, if present, not sharply demarcated from forehead Go to 19 



b. Head has a distinct, though sometimes short rostrum separated from the forehead by a distinct crease angle ... Go to 30 



19. a. Teeth spade-shaped, laterally compressed and relatively small; body to only about 5 feet (1.5 m); 



22-28 teeth in each upper and lower jaw. 



Harbor porpoise, p. 150 

 b. Teeth conical and sharply pointed (in cross section circular, or slightly flattened anteroposte- 



riorly Go to 20 



20. a. No distinct dorsal fin; back marked instead with small dorsal ridge near midpoint of back Go to 21 



b. Distinct dorsal fin, in middleor forward third of the back Go to 22 



21. a. 8-11 teeth in each upper jaw, 8-9 in each lower jaw; body of young slate gray or brownish, adults 



white; short broad rostrum. 



Beluga, p. 99 

 b. No visible teeth (or two teeth) in upper jaw of adults only; in males and sometimes females one or both 

 of these may grow up to 9-foot (2.7-m) tusk in left-hand (sinestral) spiral; no rostrum. 



Narwhal, p. 102 



' By feeling bet ween the lower jaws on the ventral surface and moving the finger forward towards the tip of the snout, one can feet the point at which the 

 two lower jaws become united (called the symphysis). This location is an important reference point in distinguishing among the species separated in 

 paragraphs 14. 15. and 16. 



166 



