estern and southern Greenland and Davis Straits,
though they are apparently far more numerous to the north of this range.
They appear in Davis Straits in spring and summer and leave that area in
autumn, sometimes as late as November, to move southward. They winter as
far south as Cape Cod, where they are the common dolphin species in
April, May, and June (sometimes to July). Their migrations are poorly
known.

Stranded Specimens

Stranded white-beaked dolphins can be most readily distinguished from
white-sided dolphins by the substantial differences in coloration and
the differences in numbers of teeth.

ATLANTIC WHITE-SIDED
WHITE-BEAKED DOLPHIN DOLPHIN

TEETH

22-28 per side per jaw. 30-40 per side per jaw,
sometimes more in upper
jaw.

COLORATION

Beak sometimes gray or Beak all black; side marked
white above and below; two with elongated areas of
pale areas visible on living white with streaking patterns
animals not visible on stranded of yellow and tan.
specimens.

Additional characteristics by which the two species may be distinguished
are summarized on p. 123.

[Illustration: Figure 140.--Two views of white-beaked dolphins off
Newfoundland. This species is characterized by a prominent uniform dark
gray dorsal fin and two areas of paleness on the sides, one in front of
and one below and behind the dorsal fin. White-beaked dolphins are
distributed from Newfoundland north, extending to more northerly waters
than Atlantic white-sided dolphins. (_Photos by H. E. Winn (bottom) and
W. A. Watkins (top)._)]

[Illustration: Figure 141.--White-beaked dolphins reach nearly 10 feet
(3.1 m) in length. Stranded animals, such as this specimen from
Scotland, should be distinguishable from Atlantic white-sided dolphins
by their differences in coloration. This species sometimes has a white
beak and always lacks the elongated white patch and tan or yellow
streaking found on the side of Atlantic white-sided dolphins. (_Photos
by A. S. Clarke._)]

ATLANTIC BOTTLENOSED DOLPHIN (T)

_Tursiops truncatus_ (Montague 1821)

Other Common Names

Bottlenosed porpoise, gray porpoise, common porpoise.[12]

[Footnote 12: See also p. 150 for use of this common name for a