ad with small dorsal
ridge near midpoint of back. Go to 21

b. Distinct dorsal fin, in middle or 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

22. a. Head long and conical Go to 23

b. Head blunt Go to 24

23. a. 20-27 teeth in each upper and lower jaw; crowns of teeth often
marked with many fine vertical wrinkles; body to about 8 feet
(2.4 m).
Rough-toothed dolphin, p. 135

b. 26-35 teeth in each upper and lower jaw; teeth smooth; body to
about 5.6 feet (1.7 m); distribution restricted to northern coast
of South America, in the Guianas, and adjacent eastward territory
of Venezuela.
Guiana dolphin, p. 132

24. a. Teeth usually at front end of lower jaw only, 2-7 pairs
(rarely teeth in upper jaw); all teeth may have fallen out of the
lower jaw of older specimens or may be extensively worn; forehead
with median crease; dorsal fin tall and distinct to 15 inches
(38.1 cm); body to 13 feet (4.0 m).
Grampus, p. 96

b. Teeth in both upper and lower jaws, 7 or more pairs, forehead
with no median crease Go to 25

25. a. Flippers large and paddle-shaped, ovate, and rounded on the
distal end; dorsal fin tall and erect to 6 feet (1.8 m) in males
and 3 feet (0.9 m) in females; 10-12 teeth in each jaw; teeth to
1 inch (2.5 cm) in diameter.
Killer whale, p. 84

b. Flippers long and pointed Go to 26

26. a. Dorsal fin located in forward one-third of body, very broad at
the base; head bulbous.
(Pilot whale)