front; frequently all distinctly bottlenosed.
white in larger animals.
MARKINGS
Very often extensively Less frequently scratched
scarred. and scarred.
Distribution
Grampus are known to be distributed in temperate and tropical seas from
at least eastern Newfoundland, south at least to St. Vincent, Lesser
Antilles, and in the eastern and northern Gulf of Mexico. The species
may not be as rare as the paucity of records suggests. Though they have
been seen in Buzzards Bay on several occasions, grampus generally have
an oceanic range and, along the Atlantic coast of North America, may be
distributed from the Gulf Stream seaward, outside the theater of normal
boating traffic.
Stranded Specimens
Stranded grampus are most readily identifiable by 1) the presence of
only seven, or fewer, teeth in each side of the lower jaw (many of those
teeth may have dropped out in older animals and remaining teeth may be
extensively worn) and the absence of teeth in the upper jaw; 2) the
presence of a distinct crease or bifurcation in the melon on the extreme
front of the head; 3) the presence of numerous scratches and scars all
over the body; and 4) the tall, slender, sharply falcate dorsal fin
which may be more than 15 inches (38.1 cm) tall.
[Illustration: Figure 103.--Grampus are frequently found in small tight
groups "porpoising." From a distance they may resemble the Atlantic
bottlenosed dolphins, though grampus have taller dorsal fins, blunted
beakless heads, and lighter coloration. (_Photo off Washington State by
C. Fiscus._)]
[Illustration: Figure 104.--Grampus off Fistler, Scotland (top) and from
Baja California in the tank of Sea World, Inc., San Diego, Calif.
(bottom). Note the tall pointed dorsal fin, which remains dark even in
adult animals, the blunted head, which lacks a beak, and the extensive
scarring of the body. In the photo on the right, note also the long
pointed flippers and the white head characteristic of older animals.
(_Photos by A. S. Clark (top) and courtesy of D. K. Caldwell
(bottom)._)]
[Illustration: Figure 105.--Grampus, particularly younger animals, have
two regions of grayish-white on the ventral surface, one in front of the
flippers and another beginning on the belly narrowing towards the tail.
These markings closely resemble the ventral marking of pilot whales.
(_Photos courtesy of Marineland of Florida._)]
[Illustration: Figure 106.--Stranded grampus can be readily identified.
On this captive animal note the blunted head, the distinct crease on the
front of the head (see also Fig. 107), and the extensive scarring of the
body. (_Photo courtesy of D. K. Caldwell._)]
[Illustration: Figure 107.--Grampus have seven or fewer teeth in each
side of the lower jaw. (None in the upper jaw.) Many of these teeth may
have fallen out of older specimens, and the remaining teeth may be
extensively worn. (_Photo courtesy of Marineland of Florida._)]
Medium-sized Whales Without a Dorsal Fin
BELUGA (T)
_Delphinapterus leucas_ (Pallas 1776)
Other Common Names
White porpoise, white whale, belukha, sea canary, marsouin blanc
(Quebec).
Description
Belugas reach a maximum overall length of about 16 feet (4.9 m). Males
are slightly larger than females. In the western North Atlantic they
have been found to grow to greatest lengths in oceanic environments near
the southern extremities of their ranges, though they are found in far
greater abundance in estuarine areas of the Arctic. Belugas have
extremely robust bodies tapering to a distinct "neck" region and a very
small head relative to body size.
They do not have a dorsal fin. Instead, along the back just behind the
midpoint there is a narrow ridge notched laterally to form a series of
small bumps. These ridges may be clearly visible on a swimming animal.
Newborn belugas are brown. As they age, they gradually lighten through
slate gray, and by their sixth or seventh year have assumed the
all-white coloration characteristic of adult animals.
Natural History Notes
Belugas feed on a variety of fishes (including cod and capelin), on
squid, and on a variety of benthic crustaceans.
They are frequently found in shallow bays and river mouths, where the
young are born, and occasionally ascend rivers.
May Be Confused With
Because of their limited distribution, all-white coloration and lack of
a dorsal fin, belugas are unlikely to be confused with any other species
of cetacean.
Distribution
Belugas have been reported from the Arctic Circle south as far as
eastern Connecticut, typically in estuarine habitats, though they do
range into oceanic regions. They are most abundant from the north shore
of the Gulf of St. Lawrence northward. They remain near the Arctic
Circle and in Hudson Bay to northern Greenland during winter,
undertaking migrations to the south in autumn, straggling to the
Maritime Provinces and as far as Connecticut. Belugas are regularly seen
in the St. Lawrence and Saguenay rivers throughout late spring and
summer. Return migrations to the north take place in spring.
A small population in the estuary of St. Lawrence is resident throughout
the year.
Stranded Specimens
Stranded belugas are unlikely to be confused with any other species of
cetaceans. The all-white coloration, the robust body shape with a rather
small head and a distinct neck region, and the presence of 8-11 teeth in
each of the upper jaws and 8-9 in each of the lower jaws permit positive
identification.
[Illustration: Figure 108.--A group of three belugas surfacing to
breathe off northwestern Alaska. The animal to the right has just begun
to exhale, the middle animal is in the midst of his inhalation, and the
animal on the left has completed his blow and is preparing to dive. Note
the all-white coloration and, on the center animal, the small dorsal
ridge just emerging from the water. Details of the dorsal ridge are
clearly visible in the inset photograph. (_Photos by G. C. Ray and K. G.
Hewlett (inset)._)]
[Illustration: Figure 109.--Note the robust form and the small head of
this swimming beluga off northwestern Alaska. (_Photo by G. C. Ray._)]
[Illustration: Figure 110.--Captive belugas at Vancouver public
aquarium. Note the dorsal ridge, the shape of the head and body, and the
unusually shaped flippers. (_Photo by K. C. Balcomb._)]
[Illustration: Figure 111.--Ventral view of a beluga harpooned in the
northeastern Canadian Eskimo Fishery. Note the very narrow tail, just in
front of the flukes, and the robust form of the species. Belugas have
8-9 teeth in each of the lower jaws, and 8-11 in each of the upper jaws.
(_Photo by P. F. Brodie._)]
NARWHAL (T)
_Monodon monoceros_ Linnaeus 1758
Other Common Names
Unicorn whale (historical name not currently in use).
Description
The narwhal, also known as the unicorn whale because of the long tusk
found on adult males, is one of two medium-sized whales found in the
Arctic waters of the northwestern Atlantic. They reach a maximum length
of from 15 to 16 feet (4.6 to 4.9 m) excluding the tusk. Newborn calves
are approximately 5 feet (1.5 m) long. Narwhals have small rounded heads
and a small mouth. Like the other medium-sized whale in the same region,
the beluga or white whale, the narwhal has no dorsal fin. Instead, it
has a series of bumps, approximately 2 inches (5.1 cm) high along the
midline of the back in the half nearest the tail. The ridge created by
these bumps may be readily seen on a swimming animal.
The basic coloration of the species changes slightly with age. Young
animals are uniformly dark bluish gray on the back but rapidly begin to
develop the numerous leopardlike spots on the back and sides
characteristic of adults. Those spots rarely extend onto the belly even
in old animals.
Narwhals have only two teeth. In the females, these teeth rarely emerge
from the gums. In males, one and sometimes both of those teeth grow out
the front of the snout, spiraling in a left-hand or sinistral direction,
and may reach a length of 9 feet (2.7 m). One or two tusks may also be
exposed, however, in females.
Natural History Notes
The function of the tusk in male narwhals is unknown, but it was this
feature of the animal that earned it the name "unicorn whale" and
resulted in its extensive hunting by whalers. During their annual
migrations narwhals may congregate but are commonly found in groups of
10 or fewer during the rest of the year.
Narwhals feed on a variety of organisms, including cod, rockfish,
flounder, and crabs, but their diet consists primarily of squid.
Distribution
Narwhals are found in the high arctic seas of the western North
Atlantic, primarily in Lancaster Sound and its fringes. It has been
noted that they are found in isolated pockets within that range and are
not, like the beluga, widely distributed.
Narwhals make annual migrations in response to the movement of the ice.
During the fall as the ice begins to form, the whales migrate to the
south, sometimes reaching the Labrador coast. In the spring they return
to the pack ice.
May Be Confused With
Narwhals are so different in coloration from the only medium-sized
cetacean which shares its range and habitat--the beluga--that the two
are highly unlikely to be confused. Belugas are usually all white or
light slate gray in color, 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.]
Description
Atlantic spotted dolphins reach a maximum adult length of 7.5, perhaps 8
feet (2.3 to 2.4 m). They are generally more robust in body shape than
the other species of Stenella, closely resembling Atlantic bottlenosed
dolphins in that regard, though the Atlantic spotted dolphins tend to be
more slender.
The dorsal fin is distinctly back-curved and pointed on the tip, also
closely resembling that of the Atlantic bottlenosed dolphin.
As the common name suggests, the Atlantic spotted dolphins are marked
dorsally with numerous grayish-white spots on a darker background and
ventrally with dark spots on a lighter background, though the extent of
the spotting and the additional details of coloration change with age.
Immature animals lack spots completely. They are dark gray or purplish
gray on the back, becoming lighter gray on the sides and white on the
belly. The cape along the back is distinctly separated from the lighter
gray coloration of the sides. The flippers and the trailing edge of the
flukes are darker than the rest of the body.
As they age, the Atlantic spotted dolphins develop grayish-white spots,
first low on the sides, spreading upward. During this stage, the cape
becomes less distinct, and dark spotting begins to develop on the belly,
the spots increasing in number with increasing age. In adult animals,
the belly is often extensively covered with dark blotches but never
becomes completely black. The lips may be white, and the beak is
characteristically tipped with white, a feature which may aid in
identification at sea.
The Atlantic spotted dolphins have a spinal blaze and a light line which
extends from the flipper to the eye.
Natural History Notes
Little is known of the natural history of the Atlantic spotted dolphins.
The species occurs in herds of up to several hundred individuals,
though groups of 50 or fewer (6-10) are more common. They are often seen
jumping clear of the water and habitually ride the bow wave of moving
vessels. As they do, the distinct cape or band of purplish gray on the
back of younger animals and the spotting pattern of older animals may be
visible.
Atlantic spotted dolphins feed primarily on squid but may also take
carangid fishes, small eels, herring, or anchovies.
May Be confused With
Atlantic spotted dolphins, particularly young animals, may be easily
confused with Atlantic bottlenosed dolphins because of the similarities
in color pattern and general body shape. However, the Atlantic spotted
dolphins have considerable purplish gray in their background colors and
the Atlantic bottlenosed dolphins are more dark gray to brownish gray.
This along with considerable differences in the overall sizes of the two
species should permit positive identification. In general, the key
differences between spotted and bottlenosed dolphins are as follows:
ATLANTIC SPOTTED ATLANTIC BOTTLENOSED
DOLPHIN DOLPHIN
MAXIMUM SIZE
To 7.5-8 feet (2.3-2.4 m). To 8-10 feet (2.4-3.1 m)
inshore, to as much as 12 feet
(3.7 m) offshore.
BODY COLOR
Dark purplish gray on back; Dark gray on back; lighter
lighter gray on sides and gray on sides; white or pink
belly; body becomes on belly (old animals may
increasingly spotted with age. have a few spots on belly,
but most are not spotted).
HEAD AND BEAK
Head more slender; beak Head robust; beak short;
longer; lips and top of snout beak usually uniformly gray
often white. (older animals' beak may be
white at tip).
NORMAL DISTRIBUTION
Usually found more than 5 Usually more coastal, often
miles offshore; most common ascending rivers and entering
inside 100-fathom curve. lagoonal and estuarine
areas.
Young Atlantic spotted dolphins are so similar in appearance to the
Atlantic bottlenosed dolphins that the frequent reports of mixed schools
of the two species are probably occasioned by groups of spotted dolphins
which include some young, still unspotted animals.
Atlantic spotted dolphins might also be confused with bridled dolphins.
The two can be most readily distinguished by the following
characteristics:
ATLANTIC SPOTTED DOLPHIN BRIDLED DOLPHIN
BODY SHAPE
Usually robust, often like More slender, more like
that of the Atlantic that of the Atlantic striped
bottlenosed dolphin. dolphin.
BODY COLOR
Spotted; purplish gray on Spotted; side of head light
back; lighter gray on sides gray; body has stripe from
and belly becoming flipper to corner of mouth,
increasingly spotted with age. though the stripe tends to
As animals becomes more fade as spotting increases.
spotted, cape become less Cape on top of head more
distinct. Body has spinal distinct that on Atlantic
blaze and light line from spotted dolphin. Body has no
flipper to eye. spinal blaze.
At sea the Atlantic spotted dolphins may also be confused with
rough-toothed dolphins (p. 135).
Distribution
Atlantic spotted dolphins are a common species in the continental waters
of the tropical and warm temperate western North Atlantic. Although they
are far more abundant south of Cape Hatteras, they have been reported
from the latitude of Cape May, N.J. (some fishermen claim to have seen
them even further north) south through the Gulf of Mexico and the
Caribbean to Venezuela. Atlantic spotted dolphins may be replaced around
the West Indies by the bridled dolphin.
Within this range, the Atlantic spotted dolphins appear to be generally
restricted to the waters outside the 100-fathom curve, most commonly
more than 5 miles offshore. However, populations in the Gulf of Mexico
move inshore in the late spring, and may approach close to shore during
spring and summer.
Stranded Specimens
Stranded Atlantic spotted dolphins may be difficult to distinguish from
bridled dolphins. If the color pattern is still clearly visible, the
differences in coloration described above, particularly those of the
head, and the presence or absence of a spinal blaze may be used. But
since external appearance other than coloration are often very similar,
specimens should be photographed from as many aspects as possible and
the entire specimen or the roughed-out complete skeleton transported to
a museum for preparation and examination. Tooth counts recorded for the
two species to date are also very similar.
[Illustration: Figure 115.--Atlantic spotted dolphins beside a research
vessel off Beaufort, N.C., September 1965. Adults of this species can be
identified by the spotting pattern and the white coloration of the lips.
(See also bridled dolphin, p. 108.) Young animals which lack spots may
be confused with the Atlantic bottlenosed dolphins though they are
smaller and are purplish gray on the back. (_Photo by G. T. Green._)]
[Illustration: Figure 116.--A side view of two female Atlantic spotted
dolphins from off St. Augustine, Fla. in the tank at Marineland of
Florida. Note the tall falcate dorsal fin, pointed on the tip and
varying slightly in shape between the two individuals, and the spots on
the body. (_Photo by S. Leatherwood._)]
[Illustration: Figure 117.--A series showing the development of the
color pattern of the Atlantic spotted dolphins from Florida. Newborn or
young animals are dark purplish gray on the back, grading to immaculate
white on the belly. As they mature, animals develop light spots, first
on the lower sides, then higher on the back, and dark spots on the
belly. As spotting increases, the cape becomes less distinct. (_Photos
by A. Solis (a), D. K. Caldwell (b, c), and courtesy of Marineland of
Florida (d, e, f)._)]
[Illustration: Figure 118--Juvenile Atlantic spotted dolphins at sea in
the southeastern Caribbean. Although spotters can be either relatively
short-snouted and chunky or long-snouted and slightly built, the spinal
blaze, flipper-to-eye stripe, white lips, and falcate dorsal fin can be
used to identify them. (_Photo by D. Poppe._)]
[Illustration: Figure 119.--A captive Atlantic spotted dolphin from off
St. Augustine, Fla. This species has from 30 to 36 teeth in each upper
jaw and from 28 to 35 in each lower jaw, fewer than all other Stenella
except perhaps the bridled dolphin, fewer than the saddleback dolphins,
but more than the Atlantic bottlenosed dolphins. (_Photo by S.
Leatherwood._)]
BRIDLED DOLPHIN (T)
_Stenella frontalis_ (G. Cuvier 1829)
Other Common Names
Bridled spotted dolphin, Cuvier's dolphin, gamin (St. Vincent), bridled
porpoise.
Description
Bridled dolphins, the second species of spotted dolphins in the western
North Atlantic, reach an adult length of at least 7 feet (2.1 m). Like
the other, the Atlantic spotted dolphin (p. 104), bridled dolphins are
characterized by light grayish-white spots on the dark dorsal portions
of the body and dark spots on the light ventral surface. Other details
of the coloration differ somewhat. Bridled dolphins are dark gray on the
back, fading to lighter gray on the sides and belly. They lack the
spinal blaze characteristic of Atlantic spotted dolphins. Except on the
head, the border between the back and side colors is indistinct. On the
head, the cape (the dark color of the top of the head) is distinct. In
the light gray of the side of the head are the markings from which the
species derives its common name, "bridled dolphin." These are a black
circle around the eye with an extension to the junction (apex) of the
rostrum and the melon (present in nearly all dolphins) and a broad black
stripe from the origin of the flipper to the corner of the mouth. This
mouth-to-flipper stripe tends to fade as spotting increases. Both the
upper and lower lips are white or pinkish.
Natural History Notes
Virtually nothing is known of the natural history of bridled dolphins
except that they have been observed in small herds of from 5 to 30
individuals and sometimes ride the bow wave of a vessel.
May Be Confused With
At sea, bridled dolphins may be confused with Atlantic spotted dolphins
or spinner dolphins. Differences by which they may be distinguished from
the first are tabularized on p. 105. Differences between spinner and
bridled dolphins permitting identification at sea are as follows:
BRIDLED DOLPHIN SPINNER DOLPHIN
COLORATION
Distinct cape on top of head; Dark gray on back; tan or
side of head light gray; yellowish tan on sides; white
distinct stripes from flippers on belly,
to corner of mouth and from
dark circles around eye to
apex of melon.
BEAK
Shorter and more slender; all Extremely long and slender;
black; lips white. dark gray to black on top,
white below; lips black.
DORSAL FIN
Uniformly dark gray. Often lighter gray in middle,
dark around border.
Distribution
Bridled dolphins occur in tropical and subtropical waters primarily near
coastal areas and islands, but are best known from the West Indies. They
have been reported from the Antilles, from Texas, and from Florida north
to North Carolina. It has been speculated that this species replaces the
Atlantic spotted dolphin around the West Indies.
Bridled dolphins have not yet been described from the South American
coast.
Stranded Specimens
Bridled dolphins have from 29 to 34 teeth in each upper jaw and from 33
to 36 in each lower jaw. They can be distinguished from spinner
dolphins, which have 46-65 teeth in each jaw, by this character alone.
They may be distinguished from spotted dolphins only if the color
pattern of the head is clearly visible. If it has faded, the specimen
will probably require 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)