museum preparation and examination before it can
be positively identified.

[Illustration: Figure 120.--A bridled dolphin harpooned in the
commercial whale fishery off St. Vincent, Lesser Antilles. If the color
pattern has faded, bridled dolphins cannot be readily distinguished from
the Atlantic spotted dolphins and must be sent to a museum for
preparation and examination of the skull and skeleton. (_Photo by W. A.
Huck, courtesy of Marineland of Florida._)]

[Illustration: Figure 121.--A bridled dolphin from St. Vincent, Lesser
Antilles. Note the dark cape of the back, the lighter side, and the dark
stripes from the eye to the snout (found in most dolphin species) and
the flipper to the gape, a feature which fades as the animal's spotting
increases. Together these two features comprise the "bridle" from which
the common name derives. Note also the white lips and the white lower
jaw. (_Photo by J. R. Sullivan._)]

SPINNER DOLPHIN (T)

_Stenella longirostris_ Gray 1828

Other Common Names

Long-snouted dolphin, long-beaked porpoise, spinner porpoise, rollover
(St. Vincent).

Description

Spinner dolphins reach a maximum length of about 7 feet (2.1 m). The
body is slender. The beak varies from extremely long and slender (Fig.
123) to relatively short (Fig. 125); the beak is usually dark on top and
clean white below, though there may be some white above. The tip of the
snout and the lips are distinctly black, while those of both species of
spotted dolphins are light. The back is dark gray to black, the sides
are tan to yellowish brown, and the belly is white. Some of the larger
animals appear almost all black with faint, light speckling. The dorsal
fin is generally moderately falcate, but may be almost triangular in
adult males. It is often a lighter gray near the middle, bordered by
black or dark gray.

Natural History Notes

Spinner dolphins derive their common name from their habit of leaping
clear of the water and spinning on their longitudinal axis. The reasons
for this behavior are unknown. Individuals may rotate 2 times, or more,
in one leap but spinning behavior is not observed as frequently in the
western North Atlantic as it is in the eastern tropical Pacific.

Spinner dolphins occur in herds of up to several hundred individuals and
are often seen jumping clear of the water, working the sea surface into
a froth. They frequently come to the bow of a boat from considerable
distances to ri