o 12

10. a. Body more than 13 feet (4.0 m); head massive, to one-third of
body length; blowhole located far forward of eyes and to left
front of head; dorsal fin low, triangular or rounded followed by
series of knuckles or crenulations; 18-25 teeth in each lower jaw
fit into sockets in upper jaw (10-16 upper teeth rarely emerge).
Sperm whale, p. 57

b. Body less than 13 feet (4.0 m); head considerably less than
one-third body length; blowhole located approximately even with
eyes on top of head, slightly displaced to left but not on left
front of head; conspicuous dorsal fin present; 8-16 teeth in each
lower jaw fitting into sockets in upper jaw Go to 11

11. a. No creases on throat; dorsal fin small and located in latter
third of back; 12-16 teeth (rarely 10-11) in each lower jaw.
Pygmy sperm whale, p. 144

b. Inconspicuous creases on throat; dorsal fin tall and falcate,
resembling that of the Atlantic bottlenosed dolphin, and located
near middle of back; 8-11 (rarely 13) extremely sharp teeth in
each lower jaw; rarely 1-3 teeth in each upper jaw.
Dwarf sperm whale, p. 148

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. No teeth at the tip of the lower jaw Go to 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[20] more than
one-fourth the length of the entire lower jaw.
True's beaked whale, p. 77

b. Tw