olor, while narwhals are very much darker, ranging
from bluish gray to brownish, and are often covered with light
leopardlike spots. Furthermore, the body of the beluga is more robust.

Further, swimming narwhals frequently buck their heads up to breathe, a
behavior which makes the tusk of adult males visible and permits
positive identification.

Stranded Specimens

Stranded narwhals should be easily identifiable by the distinctive
coloration and the unique characteristics of the teeth. In adults, one
or two of the teeth may develop into the long, left-hand spiraling tusk,
shown in Figures 112 and 114. Immature animals have no teeth which are
emerged.

[Illustration: Figure 112.--In this photo of narwhals, the origin of the
name "unicorn whale" is apparent. The animal at the right, an adult
male, exposes his tusk as he surfaces aggressively to breathe. Even when
this feature is not observed, however, the narwhals' mottled gray
coloration makes them easy to distinguish from the all-white belugas,
with which they share a common range. Note also the dorsal ridge on the
animal to the left. (_Photo by D. Lusby, courtesy of the Sea Library._)]

[Illustration: Figure 113.--A juvenile narwhal in a tank at New York
Aquarium. Though newborn animals are dark bluish gray on the back,
fading to white on the belly, note that the mottled gray coloration
characteristic of adults is well developed even in relatively young
animals. The white region on the head is lanolin cream, applied to
protect the animal's skin during transport. (_Photo by H. E. Winn._)]

[Illustration: Figure 114.--A stranded male narwhal. The long unicorn
tusk is the spiral extension of one of the two teeth, though the other
may be exposed above the gums in males and may even develop into a
second long tusk; both teeth of females are normally buried in the gums
and rarely emerge. Note the highly distinctive dorsal ridge, near the
midpoint of the back. (_Photos by D. Lusby, courtesy of the Sea
Library._)]

Small Whales, Dolphins, and Porpoises With a Dorsal Fin

ATLANTIC SPOTTED DOLPHIN (T)

_Stenella plagiodon_ (Cope 1866)

Other Common Names

Spotter, Gulf Stream spotted dolphin, spotted porpoise, long-snouted
dolphin.[11]

[Footnote 11: See also p. 110. The common name "long-snouted dolphin"
was once widely used for this species. It is now more frequently used
for _Stenella longirostris_, also known as the spinner dolphin.]

Desc