- 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[20] 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]
- b. A single pair of teeth back of united portion of lower jaw; body less than 17 feet (5.2 m)
- Go to 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 anteroposteriorly)
- 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 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) Go to 27
- b. Dorsal fin located near midpoint of back; head long
- Go to 28
- 27. a. Flippers one-fifth of body length, or more.
- Atlantic pilot whale, p. [91]
- b. Flippers one-sixth of body length, or less.
- Short-finned pilot whale, p. [94]
- 28. a. Flipper has distinctive hump on forward margin; 8-11 prominent teeth curved backwards and inwards, in each upper and lower jaw.
- False killer whale, p. [88]
- b. Flipper lacks distinctive hump on forward margin; 10-25 teeth in each upper and lower jaw
- Go to 29
- 29. a. 8-13 teeth in each jaw.
- Pygmy killer whale, p. [138]
- b. 20-25 teeth in each upper jaw, 21-24 teeth in each lower jaw.
- Many-toothed blackfish, p. [142]
- 30. a. Beak short, usually less than about 1 inch (2.5 cm)
- Go to 31
- b. Beak more than 1 inch (2.5 cm)
- Go to 33
- 31. a. Flippers very short; dorsal fin small and triangular; 38-44 teeth in each jaw; body to at least 8 feet (2.4 m); distinct black stripe from beak to area of anus; in profile beak shows very little separation from forehead.
- Fraser's dolphin, p. [120]
- b. Flippers long relative to body length; dorsal fin tall and distinctly falcate; 22-40 teeth in each jaw; in profile, beak shows distinct separation from forehead.
- (Lagenorhynchus sp.) Go to 32
- 32. a. 22-28 teeth in each jaw; dorsal fin all black; body to about 10 feet (3.1 m).
- White-beaked dolphin, p. [126]
- b. 30-40 teeth in each jaw (some animals have greater number in upper than in lower jaw); dorsal fin part gray, part black; body to about 9 feet (2.7 m).
- Atlantic white-sided dolphin, p. [123]
- 33. a. 20-26 teeth in the upper jaws; 18-24 in the lower jaws; body to 12 feet (3.7 m); teeth may be extensively worn.
- Atlantic bottlenosed dolphin, p. [128]
- b. 26 or more teeth in both upper and lower jaws
- Go to 34
- 34. a. 29-36 teeth in each upper jaw; 28-36 in each lower jaw.
- (Spotted dolphins) Go to 35
- b. More than 40 teeth in each upper and lower jaw
- Go to 36
NOTE: Characters in paragraph 35 are usable only on fresh specimens. Spotted dolphins in advanced stages of decomposition can be distinguished only with museum preparation and examination.
- 35. a. Bridle present (dark lines from eye to rostrum and from flippers to corner of mouth); cape on head distinct; no spinal blaze.
- Bridled dolphin, p. [108]
- b. Bridle absent though there is a light line from the flipper to the eye; cape indistinct; spinal blaze.
- Atlantic spotted dolphin, p. [104]
- 36. a. From 46-65 small, sharply pointed teeth; body dark gray on back, tan to light gray on sides, white on belly; beak dark gray or black above, white below, and often black-tipped; body to about 7 feet (2.1 m).
- Spinner dolphin, p. [110]
- b. From 40 to 50 teeth in each upper and lower jaw
- Go to 37
- 37. a. Body to 9 feet (2.7 m); black to dark gray on back, gray on sides, white on belly; distinctive black stripes from eye to anus, eye to flipper, and dark dorsal coloration to side above flipper.
- Striped dolphin, p. [113]
- b. Body to 8.5 feet (2.6 m) but usually less than 7.5 feet (2.3 m); body dark on back with light thoracic patch and crisscross or hourglass pattern on side; black stripe from middle of lower jaw to origin of flipper.
- Saddleback dolphin, p. [116]
[18] Counts of ventral grooves are made between the flippers and do not include shorter grooves often found on the side of the head and on the side above the flippers.
[19] Blue whale has faint lateral ridges.
[20] By feeling between the lower jaws on the ventral surface and moving the finger forward towards the tip of the snout, one can feel 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.