Chapter II: Part 2

Body to about 9 feet (2.7 m) long.
Body dark steel gray on back; lighter gray on sides; pinkish to
white on belly.
Head blunt; jaw underslung; false gills or bracket marks on side
of head.
Body has two small creases on throat.
Dorsal fin like that of Atlantic bottlenosed dolphin; located
near midpoint of back.
Has not been reported to ride bow waves.
Distribution poorly known; at least from Georgia to the tropical
seas.

[Sidenote: HARBOR PORPOISE

_Phocoena phocoena_

p. 150]

Body to 5 feet (1.5 m) long.
Body dark brown above and white below; transition zone on sides
often speckled or streaked; ventral white extends high onto
side in front of dorsal fin.
Head rounded; beak small and indistinct.
Dorsal fin short and triangular.
Distribution in shallow waters from at least Delaware north;
generally found inshore; often in bays, river mouths and
inlets.
Does not approach boats.

SPECIES ACCOUNTS

Large Whales With a Dorsal Fin

BLUE WHALE (B)[9]

_Balaenoptera musculus_ (Linnaeus 1758)

[Footnote 9: The letter in parentheses indicates whether the species is a baleen (B) or a toothed (T) whale.]

Other Common Names

Sulphur-bottom.

Description

Blue whales are the largest living mammals. Though reports of maximum length and weight vary from one account to another, Antarctic blue whales are known to have reached lengths to 100 feet (30.5 m) and weights of over 150 tons (136,363 kg)[10] before stocks were severely depleted by whaling operations. North Atlantic blue whales may be expected to reach lengths of 80-85 feet (24.4-25.9 m). In all known populations of blue whales, females are slightly larger than males of the same age.

[Footnote 10: The largest measured specimen was "just over" 100 feet (30.5 m); the largest specimen weighed, the 150-ton individual noted above, was 89 feet (27.1 m) long.]

Viewed from above, the blue whale's rostrum is broad, flat, and nearly U-shaped (actually shaped like a Gothic arch, slightly flattened on the tip), with a single ridge extending from the raised area just in front of the blowholes towards but not quite reaching the tip of the snout.

The dorsal fin is extremely small [to only 13 inches (33 cm)] and variable in shape from nearly triangular to moderately falcate. In all cases, it is located so far back on the animal's tail stock that it is seldom visible until the animal is about to begin a dive.

Blue whales are light bluish gray overall, mottled with gray or grayish white. Some animals may have yellowish or mustard coloration, primarily on the belly, the result of the accumulation of diatoms during long stays in the cooler waters to the north. The undersides of the flippers are light grayish blue to white.

The baleen plates are all black.

Natural History Notes

The blow or "spout" is tall, to perhaps 30 feet (9.1 m), slender, vertical, and not bushy, as is the blow of humpback whales, for instance.

Although the blowing and diving patterns of blue whales may vary, depending on the speed of movement and the activity of the whale when it is encountered, they may be generally described as follows: If the animal is moving slowly, the blowhole and part of the head may still be visible when the dorsal fin breaks the surface, and the animal may settle quietly into the water without exposing the last portion of the tail stock or the tail flukes. If the animal is moving more quickly, however, or is about to begin a long dive, the blowhole disappears below the surface, a broad expanse of the back is exposed and disappears, and the dorsal fin emerges briefly just before the animal lifts its tail stock and flukes slightly above the surface before slipping out of sight.

In this species it can be generally stated that the maximum height of back in the area of the dorsal fin which is exposed above the surface as the animal sounds is approximately four times the height of the dorsal fin itself. The exposure of the tail flukes is unlike that of the humpback whale (Fig. 39), the right whale (Fig. 50), or the sperm whale (Fig. 57) in that when beginning a long dive all these other species raise the flukes high out of the water and usually descend at a steep angle. Blue whales lift the flukes only slightly, if at all.

Blue whales are relatively shallow feeders, feeding as they do almost exclusively on "krill" (small shrimplike crustaceans), most of which are distributed in the surface 330 feet (100 m). Blue whales usually occur singly or in pairs.

May Be Confused With

At sea, blue whales may be confused with fin whales (p. 26) and though the two are sometimes difficult to distinguish from a distance, the following key differences permit identification at close range:

BLUE WHALE FIN WHALE

COLORATION

Mottled bluish gray above Gray above, white below; frequently
and below. grayish-white chevron
behind head, right lower
lip white.

BALEEN

All black. Bluish gray with yellowish-white
strips; front fifth to
third of baleen on right side
all white.

HEAD

Broad and nearly U-shaped; Narrower, more V-shaped;
all dark. right lower lip white.

DORSAL FIN

To 13 inches (33 cm); triangular To 24 inches (61 cm); falcate;
to moderately falcate; in located slightly more than a
last third of back; visible well third forward from tail
after blow. flukes; usually visible shortly
after blow.

SURFACING AND PREPARING TO DIVE

Often shows head and blowholes; Usually rolls higher out of
broad expanse of back water, particularly on long
and much later, dorsal fin. dive; dorsal fin visible shortly
after blow.

DIVING

Dives for 10-20 min; surfaces Dives 5-15 min (most often
and blows 8-15 times, making 6-7); surfaces steeply for 3-7
a series of 12- to 15-s dives blows then dives rather
between blows, then disappears steeply again; does not show
again; sometimes raises flukes on dive: on sounding,
flukes slightly on last dive; the maximum height of back
on sounding, the maximum in the area of dorsal fin which
height of back in the area of is exposed is approximately 2
dorsal fin which is exposed is times the height of the dorsal
approximately 4 times the fin.
height of the dorsal fin.

GROUPING

Usually found singly or in Occasionally found singly or
pairs. in pairs, more often found in
pods of six or seven individuals;
many pods, consisting of
as many as 50 animals, may
be found in small area.

See also comparison of fin whale and sei whale (p. 26).

Distribution

Though blue whales have been reported from the pack ice to Cristobal Harbor, Panama Canal Zone, their normal range in the western North Atlantic is more limited. In spring and summer months (about April through at least August) they can be expected in the northern portion of their range, at least as far north as the Arctic Circle, feeding on the krill abundant in those waters. A small portion of the population may venture north, beyond the Circle. In fall and winter the population moves south, presumably into temperate and perhaps to tropical waters. Reliable records include animals from observations off Long Island and Ocean City, Md.

Though southern limits of the species are poorly known, there are no records from Florida or the West Indies and no verified records from the Gulf of Mexico.

Summaries of blue whale distribution based on records when the species was more numerous indicate that they were found during spring and summer months in some abundance on the Nova Scotian Banks, the St. Lawrence Gulf and estuary, the Strait of Belle Isle, Grand Bank, and in the waters off the coasts of Iceland, southern Greenland, and the Davis Straits and Baffin Bay. (Some individuals have entered the Hudson Strait but not apparently Hudson Bay itself.)

Historically, a few animals apparently appeared off the coast of southeastern Canada as early as February. It was speculated that from there a portion of the population underwent a migration from the Strait of Belle Isle north through the Davis Straits to the waters off western Greenland. Some individuals entered the Gulf of St. Lawrence after the ice was clear and remained behind until as late as November. In the fall months, certainly by November, the northern portion of the population had begun retreating to the south in front of the advancing ice. The remainder apparently also underwent this migration as well, since blue whales have historically been nearly absent from Canadian waters during midwinter.

Many of the migrating individuals were assumed to continue south to temperate and, less frequently, to tropical water where they calved. It should be emphasized that though all of the southward and the subsequent northward migrations were presumed to be along pelagic routes, details were poorly documented.

Blue whales have been reported in both shallow inshore and deep oceanic zones.

Despite considerable attention in the popular literature to the plight of the blue whale populations and frequent statements that they are near extinction, blue whale stocks in the western North Atlantic appear more abundant than has been usually reported. While present stocks are far short of previous population sizes, which may have exceeded 200,000 individuals worldwide, they should be sufficiently large for the species to continue their increase, barring renewed exploitation.

Stranded Specimens

Stranded blue whales can be readily identified by 1) the large body size (to 85 feet [25.9 m]); 2) the broad flat head; 3) the all-black baleen plates (270-395 in number), which are usually barely more than twice as long as they are wide; and 4) the 55-88 ventral grooves extending to the navel or beyond (Table 2).

Depending on the state of decay and the position of the stranded specimen, any of the body characteristics described for living animals may also be used to positively identify the specimen.

FIN WHALE (B)

_Balaenoptera physalus_ (Linnaeus 1758)

Other Common Names

Finback whale, finner, razorback, common rorqual.

Description

Fin whales have been reported to reach 79 feet (24 m). Females are slightly larger than males of the same age.

The back is distinctly ridged towards the tail, prompting the common name "razorback" whale.

The rostrum is narrower and more V-shaped than that of the blue whale and has the same sort of single distinctive head ridge. The top of the head is flat, though slightly less than that of the blue whale.

The dorsal fin is up to 24 inches (61 cm) tall; angled less than 40 deg. on the forward margin, located slightly more than one-third forward from the tail, and appears on the surface shortly after the blow.

All individuals are dark gray to brownish black on the back and sides with none of the mottling present on blue whales and are rarely as heavily scarred as sei whales. Along the back, just behind the head, there is a grayish-white chevron, with the apex along the midline of the back and the arms of the chevron oriented posteriorly, which is sometimes distinctive and may be visible as the animals surface to breathe. The undersides, including the undersides of the flukes and flippers, are white. On the head, the dark coloration is markedly asymmetrical, reaching farther down on the left than on the right side. The right lower lip, including the mouth cavity, and the right front baleen (approximately one-fifth to one-third) are yellowish white. Occasionally the right upper lip is also white. The remainder of the plates on the right side and all those on the left side are striped with alternate bands of yellowish white and bluish gray. The fringes of the plates are brownish gray to grayish white.

Natural History Notes

Fin whales are one of the most common baleen whale species in the world and constitute a major portion of the whaling catch. They are reportedly one of the fastest of the big whales (sei whales may be slightly faster) possibly reaching burst speeds in excess of 20 knots, and were not an important commercial species until the comparatively recent development of fast catcher boats and the depletion of blue whale stocks.

A fin whale's blow can be from 15 to 20 feet (4.6 to 6.1 m) tall and has been described as an inverted cone or an elongated ellipse.

Fin whales dive to at least 755 feet (230.1 m). This depth is probably deeper than that of either blue or sei whales, a factor usually reflected in differences among the surfacing, blowing, and diving characteristics of these three species. When they are moving leisurely at the surface, fin whales expose the dorsal fin shortly after the appearance of the blowholes, slightly later than that of the sei whales. When they are surfacing from a deeper dive, however, they surface at a steeper angle, blow, submerge the blowholes, and then arch the back and dorsal fin high into the air before beginning another long dive. In this species it can be generally stated that the maximum amount of the back in the area of the dorsal fin which is exposed above the surface as the animal sounds is approximately 2 times the height of the dorsal fin. Fin whales do not show their tail flukes when beginning a dive.

Unlike blue or sei whales, fin whales do breach on occasion. When they do leap clear of the water, fin whales usually reenter with a resounding splash, like that made by humpback and right whales and not smoothly, head first, as minke whales often do.

Fin whales are sometimes found singly or in pairs but more often occur in pods of six or seven individuals and many pods consisting of as many as 50 animals may be concentrated in a small area.

Fin whales calve and breed in winter, mostly in temperate waters.

Atlantic fin whales eat a wide variety of foods, including krill, capelin, squid, herring, and lanternfish.

May Be Confused With

Fin whales may be confused with blue whales, sei whales, and, in the southernmost portion of their range, with Bryde's whales. They may be distinguished from the blue whales by differences in overall coloration, coloration and shape of the head, and the size, position, and time of appearance of the dorsal fin at the surface (see p. 19). After close examination they may be distinguished from Bryde's whales by the presence of three ridges along the head (of the Bryde's whale) and by the smaller, more sharply pointed falcate dorsal fin of the Bryde's whale (see Fig. 31). They may be distinguished from sei whales in the following similar ways:

FIN WHALE SEI WHALE

DORSAL FIN

Slightly falcate, forms angle Sharply pointed and falcate:
of less than 40 deg. with back forms angle of greater than
slightly more than one-third 40 deg. with back well more than
forward from tail. one-third forward from tail.

SURFACING BEHAVIOR

Usually rise obliquely so top Primarily skimmer feeders;
of head breaks surface first; usually rise to surface at
after blowing, animal arches shallow angle so that dorsal
its back and rolls forward fin and head are visible
exposing the dorsal fin on the almost simultaneously; when
long dive; on sounding, the starting the long dive does
maximum amount of back in not usually arch the back as
the area of the dorsal fin much as the fin whale; on
which is exposed is approximately sounding, the maximum
2 times the height of amount of back in the area of
dorsal fin. the dorsal fin which is
exposed is approximately 1
times the height of the dorsal
fin.

BLOW

Tall (to 20 feet [6.1 m]); Similar shape but smaller--rarely
inverted cone (point down) taller than 10-15 feet
or elongated ellipse. (3.1-4.6 m).

DIVING

Dive for 5-15 (usually 6-7) Dive for 3-10 min; usually
min; blow 3-7 times or more blow at even intervals over
at intervals of up to several long periods of time; often
minutes, then dive again. visible just below the surface,
even on longer dives.

COLOR OF UNDERSIDES

White higher up on right Mostly gray; irregular whitish
than on left side. area on belly.

COLOR OF LOWER LIP

White on right, gray on left. Gray.

BALEEN PLATES

Right one-fifth to one-third Ash black with a blue tinge
in front white; all others and fine grayish bristles.
alternate bands of yellowish
white and bluish gray; bristles
grayish white.

Distribution

Fin whales are probably the most numerous and widely distributed large whale species in the western North Atlantic.

Fin whales summer from below the latitude of Cape Cod, Mass., north to the Arctic Circle. (They are frequently seen between New York and Bermuda this time of year.) Within this zone they may sometimes be seen very close to shore and appear to be concentrated between shore and the 1,000-fathom curve from at least lat. 41 deg.20' to 57 deg.00' N. In recent years they have been reported in relatively large numbers in the Gulf of Maine from March through June, off Newfoundland as early as June but increasing to August, and entering Davis Straits and beyond in substantial numbers in midsummer to late summer. There is some evidence that the animals venturing farthest north are the largest individuals of the species. Movements of the population(s) southward have usually begun by October, though some fin whales sometimes remain in the northern seas sufficiently long to become trapped in the ice and killed.

During winter the range of fin whales spreads out from the advancing ice southward, reaching at least to the coast of Florida, into the Gulf of Mexico, and to the Greater Antilles, though fin whales are not at all common in tropical waters. During the winter many fin whales move into offshore waters. Northward migrations probably begin in midspring.

Fin whales may be found in Cape Cod waters all year long.

There may be two or possibly three separate stocks of fin whales in the western North Atlantic, one more northern cold-adapted stock and another more southern stock. The ranges of the two stocks appear to overlap, such that the winter range of the northern stock probably becomes the spring and summer range of the more southern stock. The third stock may consist of an isolated population in the northern Gulf of Mexico.

Stranded Specimens

Stranded fin whales may be most readily identified by 1) the yellowish-white coloration of the right front baleen and the right white lower lip; 2) the numerous baleen plates (262-473 in number); 3) the numerous ventral grooves (56-100 in number) extending to the navel and beyond (Table 2); and 4) the broad, flat sharply pointed head with only a single head ridge.

SEI WHALE (B)

_Balaenoptera borealis_ Lesson 1828

Other Common Names

Pollack whale, sardine whale, Rudolphi's rorqual.

Description

Sei (pronounced "say") whales have been reported to reach 62 feet (19 m).

The snout is less acutely pointed than that of the fin whale but when viewed from the side appears slightly arched. In general, the head is intermediate in shape between that of the blue whale and that of the fin whale. The dorsal fin, which is from 10 to 24 inches (25.4 to 61 cm) tall and strongly falcate in adult animals, is located about two-thirds of the way back on the back, farther forward than that of the blue or fin whales. Sei whales are dark steel gray on the back and sides, and on the posterior portion of the ventral surface. The body often has a galvanized appearance due to scars possibly resulting from lamprey bites inflicted during migrations into warmer waters. These scars may be dark gray to almost white in color. On the belly there is a region of grayish white that is confined to the area of the ventral grooves. Neither the flippers nor the tail flukes are white underneath. The right lower lip and the mouth cavity, unlike those of the fin whale, are uniformly gray. The baleen plates are uniformly grayish black with fine grayish-white fringes. (A small number of sei whales have been noted to have a few half-white plates near the front of the mouth, a feature which might result in their confusion with fin whales.)

Natural History Notes

The blow of sei whales is an inverted cone rarely taller than 15 feet (4.6 m).

Sei whales are generally skimmer feeders and do not usually dive very deeply. For that reason they usually surface at a shallower angle than fin whales. The head rarely emerges at a steep angle (except when the whales are chased). Instead, the blowholes and a major portion of the back, including the dorsal fin, become visible almost simultaneously and remain visible for relatively long periods of time. In this species it can be generally stated that the amount of the back in the area of the dorsal fin which is exposed above the surface as the animal sounds is approximately the same height as the dorsal fin. When they begin another dive, sei whales do not arch the tail stock or flukes high. Instead, they normally submerge by slipping quietly below the surface, often remaining in view only a few feet down and leaving a series of tracks or swirls on the surface as they move their tail flukes. When they are feeding in this manner, sei whales may exhibit a highly regular blowing and diving pattern over long periods of time.

Sei whales usually travel in groups of from two to five individuals, though they may concentrate in large numbers on the feeding grounds.

In the northern portion of their range, sei whales feed on copepods. Throughout the remainder of the range, however, their food is more varied and also includes krill and a variety of small schooling fishes. The species derived its common name, in fact, from its frequent occurrence with or near sei fish.

May Be Confused With

The sei whale's smaller size and decidedly taller, more falcate dorsal fin located well more than one-third forward from the tail should prevent confusion with the blue whale. At a distance, however, sei whales are difficult to distinguish from either fin whales or Bryde's whales. The primary clues for distinguishing them from fins are the differences in swimming, blowing, and diving characteristics tabularized in detail on p. 26 and the asymmetrical coloration of the fin whale.

Sei whales may be distinguished from Bryde's whales only upon close examination. The dorsal fin of Bryde's whales is small, to 18 inches (45.7 cm), sharply pointed, and often worn on the rear margin. If close examination is possible, the sei whale will be seen to have only a single head ridge. Bryde's whales have two additional ridges--one on each side of the main ridge. Bryde's whales are primarily fish feeders and their diving behavior more closely resembles that of a fin whale than that of a sei whale. (See p. 37).

Distribution

The distribution and migrations of the sei whale during most of the year are rather poorly known. The species is known to avoid the colder regions near the pack ice and to range from Iceland south to the northeast Venezuelan coast and the northeast and southwest Gulf of Mexico. There are also records from Cuba and the Virgin Islands. Along the northeast United States and eastern Canadian coasts, where most research on sei whales has been conducted, the species migrates from New England through the Blanford, Nova Scotia area in June and July, is found in small numbers off eastern Newfoundland in August and September (abundant in Placentia Bay, Newfoundland in August), and continues northward to the Davis Straits in September and October. An offshore stock may be found year-round in the Labrador Sea. The summer range (May to September or October) extends from New England to southern Arctic waters. Though some individuals remain behind through November, the southward movement of the bulk of the population presumably begins in October. In general, sei whales do not venture as far north as fin whales but may have a greater tendency to enter tropical waters.

Stranded Specimens

Stranded sei whales are most likely to be confused with fin whales or Bryde's whales. The three head ridges of the Bryde's whale (sei whales have only one) assist in distinguishing sei whales from Bryde's whales. They may be distinguished from fin whales and all other rorquals by the following characteristics: 1) The color of the baleen plates--uniformly ash black with a blue tinge and fine white bristles (Table 2). 2) The density of bristles on the plates--sei whales have from 35 to 60 baleen fringes per centimeter; all other rorquals have far fewer (less than 35). 3) The relative lengths of the ventral grooves--the grooves of sei whales end well before the navel; those of blue, fin, and Bryde's whales extend at least to the navel. 4) The relatively small numbers of ventral grooves (38-56)--both blue and fin whales have more; Bryde's whales have approximately the same number.

If the animal is not in an advanced state of decomposition, the region of white coloration of the belly may also be visible.

BRYDE'S WHALE (B)

_Balaenoptera edeni_ Anderson 1879

Other Common Names

None known.

Description

Bryde's whales reach a maximum length of approximately 46 feet (14 m). They closely resemble sei whales in external appearance. At a distance, the head of this species is similar in profile and general appearance to that of the sei whale. The most distinctive field characteristic of the species, however, is the presence of three ridges along the head anterior to the blowhole. In addition to the medial ridge characteristic of all the other balaenopterid species, Bryde's whales have two secondary ridges on the top of the head--one along each side even with the blowhole running forward towards the tip of the snout. If they can be examined at close range, Bryde's whales can be positively identified by this character alone.

The dorsal fin of Bryde's whales is up to 18 inches (45.7 cm) tall, extremely falcate, pointed on the tip, located well more than one-third forward from the tail, and is often irregularly notched or frayed on the rear margin from unknown causes. Bryde's whales are dark gray overall, though some individuals, like some minke whales, have a small region of gray on each side just forward of the dorsal fin.

Natural History Notes

Bryde's whales, like minke whales, reportedly often approach close to vessels as if curious about them. During this time they may be examined carefully and their identifying characteristics seen.

Though euphausiids may be an important food for this species in limited areas, Bryde's whales often feed on schooling fish (including pilchards, anchovies, herring, and mackerel). This food preference is reflected in the diving behavior of the species. Bryde's whales are not "skimmer" feeders; they are deeper divers. When they surface to breathe, they often rise more steeply to the surface, exposing much of the head, roll the body sharply, and hump up the tail stock before beginning another dive. In this species, as in the fin whale, it can be generally stated that the amount of the back which is exposed above the surface as the animal sounds is approximately twice the height of the dorsal fin. They apparently do not raise the tail flukes when beginning a dive.

May Be Confused With

At sea Bryde's whales may be confused with sei whales, fin whales, and perhaps minke whales.

They may be most readily distinguished from sei whales by the characteristics discussed on p. 32 and by differences in diving behavior. The shallow-feeding sei whales surface and blow at regular intervals over long periods of time. Bryde's whales are deeper divers, less likely to surface, and blow at evenly spaced intervals. If they are seen only briefly or at a distance, however, the two species may be impossible to differentiate.

During the winter months, when fin whales may venture into tropical waters, they may also be confused with Bryde's whales. But fin whales seldom exhibit curiosity about boats. In addition, the dorsal fin of the fin whale is larger, is located farther back on the back than that of Bryde's whale, and does not become visible as soon after the blow. It is also less likely to be worn on the rear margin than that of a Bryde's whale.

The head of the fin whale is more acutely pointed. Furthermore, the right lower lip and the right front baleen of the fin whale are white. The baleen and the right lower lip of Bryde's whales are dark gray. If the animals can be approached closely from the right side, positive identification is possible using these differences in color.

Like Bryde's whales, minke whales often approach close to vessels. But minke whales have an acutely pointed snout, a single head ridge, and a white band on each flipper. Further, minke whales rarely reach 30 feet (9.1 m) in maximum length.

Distribution

The distribution of Bryde's whales is rather poorly known, no doubt in part, because the species is difficult to positively identify at sea, and records of its occurrence may have often been confused with those of sei whales, fin whales, or minke whales. From stranded animals and confirmed sightings at sea, the species appears to be found primarily near shore in areas of high productivity in tropical or subtropical waters, though it ventures into warmer temperate waters as well. It has been reported from Virginia south into the northeast Gulf of Mexico and the southeast Caribbean, and southern West Indies (Curacao and Granada). To date no migration has been described for the species.

Stranded Specimens

Stranded Bryde's whales can be positively identified by the three ridges along the top of the head from the area of the blowhole to the tip of the snout. All other species of balaenopterid whales, except humpback whales have but a single ridge. If the head of a stranded specimen is buried in sand, is decomposed beyond recognition, or is otherwise inaccessible for identification, Bryde's whales can still be distinguished from sei whales by differences in the relative lengths of the ventral grooves (Table 2) and from both the fin whale and the sei whale by differences in the characteristics of the baleen plates (Table 2).

HUMPBACK WHALE (B)

_Megaptera novaeangliae_ (Borowski 1781)

Other Common Names

Humpbacked whale, bunch, hump whale, or hunchbacked whale.

Description

Humpback whales reach a length of 53 feet (16.2 m).

The body is robust, narrowing rapidly on the tail stock. The head is quite broad and rounded, somewhat like that of the blue whale. The head ridge characteristic of other balaenopterid species is indistinct and is replaced in prominence by a string of fleshy "knobs" or protuberances, many more of which are randomly distributed on the top of the head and on the lower jaw. There is a distinctive rounded projection near the tip of the lower jaw. Humpback whales carry many barnacles and whale lice. The baleen plates are all black with black or olive-black bristles.

The flippers are very long (nearly a third as long as the body), are scalloped on at least the leading edge, and are nearly all white.

The dorsal fin, located slightly more than two-thirds of the way back on the back in approximately the same position as that of the fin whale, is small and varies in size and shape from a small, triangular nubbin to a more substantial, sharply falcate fin. The dorsal fin frequently includes a step or hump, which is quite distinct when the animal arches its back to begin a dive and from which the species derives its common name.

Humpback whales are basically black in color with a white region of varying size on the belly, which upon close examination may often be seen to be crosshatched with thin dark lines; the flippers and the undersides of the flukes also are white.

Natural History Notes

The blow of humpback whales is from 8 to 10 feet (2.4 to 3.1 m) tall and has been described as balloon-shaped. It is wide relative to its height. Feeding humpback whales habitually blow 4-8 times at intervals of 15-30 s after a long dive. In the tropics they habitually blow 2-4 times in succession when beginning a long dive. In diving, humpback whales throw the tail flukes high into the air, exposing the sometimes white undersurface and the rippled rear margin.

Humpback whales often leap clear of the water, raise a flipper, and slap it against the water, or "lobtail," raising the tail high into the air and bringing it crashing back to the water in a loud report. Often, particularly when they are encountered on their tropical breeding grounds, humpback whales will be found lying on their sides with a long flipper in the air.

Humpback whales feed on krill and schooling fish.

May Be Confused With

From a distance humpback whales may be confused with any of the other large balaenopterid (rorqual) whales--blue, fin, sei, or Bryde's. Although it is highly variable, the dorsal fin most closely resembles that of the blue whale. However, it is located farther forward on the back. Humpback whales distinguish themselves from the remainder of the rorquals by their habit of raising the flukes high into the air when starting a long dive. (In very shallow water they may not raise the flukes at all.) The only other rorqual to do so--the blue whale--raises the flukes slightly or not at all.

Under some conditions humpback whales may be confused with sperm whales at a distance. When arching the back to begin a dive, both may show a distinct hump. Both species frequently raise their flukes nearly vertically when beginning a long dive but differ in several ways. The flukes of humpback whales show varying amounts of white beneath, are pointed on the tips, and are distinctly concaved and irregularly rippled on the rear margin. Those of sperm whales are all dark and more flattened and even along the rear margin. Further the species can be distinguished in the following ways:

HUMPBACK WHALE SPERM WHALE

BLOW

Projects upwards from center Projects obliquely forward
of head. Usually blows from left side of snout.
4-8 times (2-4 times in Usually blows many times
tropics) before diving. (20-50 or more) before diving.

HEAD

Raised area around blowholes, Blunted, long, smooth.
knobs on upper surface.

FLUKES

Often white underneath, Smooth, all black on rear
concaved and scalloped on margin.
rear margin, deeply notched.

FLIPPERS

Extremely long (to one-third Short; all black.
of body), white and scalloped
on leading edge.

DORSAL FIN (OR HUMP)

Triangular to falcate fin, Rounded hump, two-thirds
including a step or hump in back on back followed by
front of the dorsal fin; knuckles or crenulations.
smooth.

When they can be examined at close range, humpback whales can be easily distinguished from all other large whale species with a dorsal fin by the tuberosities or knobs on the head, by the long white flippers scalloped on the leading edge, by the small distinctive dorsal fin, and by their distinctive tail flukes.

Distribution

In the western North Atlantic, humpback whales are widely distributed from north of Iceland, Disko Bay and west of Greenland, south to Venezuela and around the tropical islands of the West Indies. They have been reported from the central and eastern Gulf of Mexico. Summer ranges extend at least from New England north to the pack ice, and feeding concentrations may be found in any portion of this region. During winter, humpback whales migrate southward to the shallow borderlands of Bermuda, to the Bahamas, and to the West Indies to calve and mate.

Stranded Specimens

The most distinctive features of stranded humpback whales are 1) the ventral grooves, 14-22 in number, very wide and extending to the navel; 2) the tuberosities of the snout and lower jaw, often the sites of numerous barnacle colonies; 3) the long flippers (to nearly a third of the total body length); and 4) the distinctive rounded projection near the tip of the lower jaw.

If these characteristics are not sufficiently clear, the species may be identifiable by the characteristics of the baleen plates (Table 2).

Large Whales Without a Dorsal Fin

BOWHEAD WHALE (B)

_Balaena mysticetus_ Linnaeus 1758

Other Common Names

Greenland whale, Arctic right whale, great polar whale.

Description

Bowhead whales, so-called because of the high-arching jaws and the resultant contour of the head, reach a maximum length of about 65 feet (19.8 m). They are extremely robust in form.

When viewed from the side, some swimming bowhead whales show two characteristic curves to the back: the first extends from the tip of the snout to just behind the blowholes; the second, encompassing the entire back, begins just behind the head and extends all the way to the tail. This character may be present only in adult animals and may be more pronounced in males. Younger animals, particularly females, are often stubbier and somewhat barrel-shaped behind the head. In all animals the back is smooth, lacking even a trace of a dorsal fin.

The head of the bowhead whale is smooth, black, and without the bonnet and the "rock-garden," the colorful clusters of callosities characteristic of the black right whale. The blowholes are widely separated, and the blow emanating from them projects upward as two separate, distinct spouts. Though two separate columns sometimes may be visible under windless conditions in the blows of most mysticetes, this feature is exaggerated and is most characteristic in the bowhead and right whales.

Bowhead whales are black overall, except for a white "vest" of uneven coloration on the chin. Within that vest, near the sides of the white zone, there may be a series of grayish black to black spots, which on some animals have been likened to a string of beads. The vest is clearly visible when a surfacing animal is viewed from the front or the side or when the animals hang vertically in the water with the head on the surface and the tail flukes down, as they do during periods of early spring mating.

Natural History Notes

Bowhead whales are usually found singly or in groups of up to three animals, though fall concentrations may include up to 50 animals.

Bowhead whales sometimes breach, throwing most of the body clear of the surface and reentering with a resounding splash.

May Be Confused With

Bowhead whales are the only species of large whales found routinely in Arctic waters. Though other species, including some of the balaenopterid whales and the right whale, may venture north as far as the southern limits of the bowhead whale and beyond, they usually do so in the spring and summer, at a time when the bowhead whales are farther to the north. Even if they are encountered together, bowhead whales can be distinguished from all the balaenopterid whales by the absence of a dorsal fin. Bowhead whales have neither a fin nor the slightest trace of a dorsal fin or ridge, while all the balaenopterids have a dorsal fin; and their back is extremely smooth, like that of the right whale. The bowhead and right whales may be readily distinguished from one another by the characters listed below for stranded specimens.

Distribution

Though bowhead whales in the western North Atlantic were once distributed from Arctic waters, from the edge of the ice, south as far as the Strait of Belle Isle and the St. Lawrence River in such abundance that they were once referred to simply as "the whale," overwhaling through the 19th century until as recently as 1911 has severely reduced their numbers and restricted their modern range. Today in addition to the more abundant populations of the Bering, Beaufort, and Chukchi seas and the Sea of Okhotsk, there are populations off eastern Greenland and in Davis Straits, Baffin Bay, James Bay, and the adjacent waters. Within these ranges, bowhead whales move southward in front of the advancing ice floes and may be expected near the southern limits of their range from September or October through the early spring months. Populations in the western North Atlantic appear to be increasing slowly.

Stranded Specimens

In addition to the fact that their ranges may overlap only slightly if at all, bowhead whales may be distinguished from the other right whales of the western North Atlantic by differences in 1) primary distribution, 2) coloration, 3) lengths of the longest baleen plates, and 4) presence of callosities.

BOWHEAD WHALE RIGHT WHALE

DISTRIBUTION

Arctic distribution south to Texas, southwest Florida
Davis Straits only during north to Iceland, reaching
winter. northern limits only during
spring and summer.

COLORATION

Black with white "vest" on Sometimes black often
front part of lower jaw, brown or mottled with regions
sometimes containing a of white on chin and
string of black spots; upper belly; patches of yellowish to
jaw lacks the "rock garden." pink callosities and lice
encrusting the snout in what
has been called a "rock
garden."

BALEEN PLATES

325-360 per side; plates to 14 250-390 per side 12
inches (35.6 cm) at base and inches (30.5 cm) at base and
longest plates up to 14 feet up to 7.2 feet (2.2 m) long.
(4.3 m) long. Dark gray or Dirty gray with black fringes;
black with gray fringes; some anterior plates
anterior margin of some partly or completely white.
plates whitish, showing
green iridescence in sunlight.

BONNET AND OTHER CALLOSITIES

Not present. Present.

RIGHT WHALE (B)

_Eubalaena glacialis_ (Borowski 1781)

Other Common Names

Black right whale, Biscayan right whale, Biscay whale, Nordcaper right whale.

Description

These right whales reach a length of about 53 feet (16.2 m).

The body is rotund and completely lacking a dorsal fin or a dorsal ridge. The upper jaw is long, narrow, and highly arched. The lips are similarly highly arched. The top of the head has a series of bumps or callosities, the largest one of which is known as the "bonnet," on the upper surface in front of the blowholes. Yellowish-brown lice and, less frequently, barnacles grow on the callosities. The color and extent of the callosities varies from one individual to the next.

The two blowholes are widely separated, resulting in the projection of the blow upward as two distinct spouts. The body is dark on the back, sometimes black, more often brown or mottled, usually has a region of white on the chin and belly, and sometimes has numerous small grayish-white scars of unknown origin. The baleen plates are up to 7.2 feet (2.2 m) long, very narrow, and variable in color from dark brownish through dark gray to black in color. When the animals swim, mouth agape near the surface, the baleen sometimes appears pale yellowish gray in color.

Natural History Notes

Right whales are usually not wary of boats and may often be approached very closely.

Like sperm and humpback whales, they usually throw their flukes high into the air when beginning a long dive.

Right whales feed primarily on copepods.

Historically, this whale was nearly exterminated by hunters, who took advantage of its slow speed and who knew that its carcass floats, to harvest these animals for their great yield of whalebone and oil. It was these characteristics which prompted whalers to dub these animals the "right" whales to kill (as opposed to the ones that were too fast to catch and sank when killed).

May Be Confused With

The distinct blow of the right whales and their smooth dark back, devoid of any traces of a dorsal fin, make it unlikely that the species will be confused with any other large whales except, perhaps, the bowhead whale. In the event that the expansion of their ranges again causes these two species to overlap in distribution, they can be distinguished from one another by the characteristics discussed on p. 49.

If only the flukes are seen as the animal begins a dive, right and bowhead whales may be distinguished from the other two species of large whales exhibiting this behavior, the sperm and the humpback, in this way: the flukes of right and bowhead whales are broad, pointed on the tips, greatly concave towards a deep fluke notch, and dark below: those of the sperm whale are more nearly triangular, while those of the humpback whale have a jagged irregular or rippled rear margin and are sometimes variously white below.

Distribution

Like its more northern relative, the bowhead whale, the right whale was once the object of a widespread and extensive whale fishery, which reduced the species to critically low numbers.

Though the former range of right whales is not clearly known, the species is thought to have been abundant from the Davis Straits south at least to the Carolinas and Bermuda and to have occurred in winter to Florida and perhaps into the Gulf of Mexico.

Currently, right whales are known from Iceland south to Florida. Animals move north along the eastern Florida coast between early January and late March. During this time the species has also been observed in the Gulf of Mexico off southwestern Florida and Texas. Right whales pass the coast of New England in fair numbers in spring and continue as far north as at least Nova Scotia. Right whales are also found off Iceland, though the migration routes to and from Iceland waters are not known. The recent apparent increases in numbers at the northern and southern coastal approaches in New England and Florida, respectively, lend credibility to the hopeful contention that the species will again recolonize its historical range.

Stranded Specimens

Stranded right whales can be easily identified by all the characters discussed on p. 49 and summarized in Table 2.

SPERM WHALE (T)

_Physeter catodon_ Linnaeus 1758

Other Common Names

Cachalot, Sea Wap (St. Vincent).

Description

Male sperm whales have been reported to reach a length of 69 feet (20.9 m), though today individuals larger than 50 feet (15.2 m) are rare. Females are much smaller, rarely exceeding 38 feet (11.6 m).

A sperm whale is among the easiest of whales to identify at sea even when comparatively little of the animal is visible. It has a huge head, which comprises from a fourth to a third of the animal's total length. (The proportion is considerably higher for males than for females.) The blunted "squarish" snout, which may project up to 5 feet (1.5 m) beyond the tip of the lower jaw, houses a large reservoir containing a high-quality oil called spermaceti.

The single blowhole is located well to the left of the midline and far forward on the head. As a consequence the small bushy blow, usually less than 8 feet (2.4 m), emerges forward at a sharp angle from the head and towards the left. Under good wind conditions this feature alone may permit positive identification of sperm whales even at considerable distances.

Sperm whales have a distinct dorsal hump, usually rounded in its appearance about two-thirds of the way back from the tip of the snout. Immediately behind the hump is a series of knuckles or crenulations along the midline. This hump and the crenulations are clearly visible when the animals arch the tail before beginning a dive. There is a ventral keel, which may also be visible as animals "sound" (dive). The flukes of sperm whales are broad and triangular in shape, are not concaved, but are deeply notched on the rear margin.

Sperm whales usually are dark brownish gray in color. The body has a "corrugated" or "shriveled" appearance. The belly and the front of the head may be grayish to off-white. The skin around the mouth, particularly near the corners, is white. The undersides of the flukes and flippers vary in color through numerous shades of browns and brownish grays.

Natural History Notes

Sperm whales may dive to depths in excess of 3,270 feet (996.7 m) for periods of an hour or more. As do most whales upon surfacing from a deep dive, sperm whales emit a single explosive blow and then, depending on the length of the dive, may remain on the surface for over 10 min and blow more than 50 times before beginning the next dive. Shorter periods on the surface and fewer blows are more common. Females may dive and remain on the surface for shorter periods of time than males. When beginning a deep dive, sperm whales throw their broad triangular flukes, dark on the undersides, high into the air.

Sperm whales may be found singly or in groups of up to 35 or 40 individuals. Older males are usually solitary except during the breeding season. During the remainder of the year large groups may be bachelor bulls (sexually inactive males) or nursery schools containing females and juveniles of both sexes. Sperm whales are seldom found in less than 600 feet (182.9 m) of water.

Sperm whales feed primarily on squid but may occasionally also take octopuses and a variety of fishes.

May Be Confused With

Because of their distinctive head shape and blow, sperm whales are unlikely to be confused with any other species when they can be closely examined. If only the back and tail flukes are seen, however, sperm whales may somewhat resemble humpback whales. Both species arch the back when beginning a dive, raising the fin or hump, and both throw the tail flukes. The most distinctive differences between the two species are tabularized on p. 40.

At sea the head of a sperm whale may also somewhat resemble that of an adult male northern bottlenosed whale, but this latter species is lighter brown in color, has a distinct beak and a prominent dorsal fin, and is rarely found south of lat. 42 deg.N. In addition, the blowhole of the northern bottlenosed whale is located well back on the head and not--as in the sperm whale--on the front.

Distribution

Sperm whales are widely distributed in oceanic areas of the western North Atlantic. They may be encountered from Venezuela north at least as far as the Davis Straits, though they apparently avoid the polar ice fields. Distribution and migrations vary between males and females. Males range farther to the north, while females and immature males remain between lat. 30 deg. and 50 deg.N. Both groups shift northward during spring and summer and return to southern portions of their range in the fall. Adult males arrive off the New England coast in August. Those reaching the Newfoundland and Labrador coasts arrive from the deep sea, perhaps following the slope contours, in August and September. Males are abundant as far north as southeast Greenland and Iceland in summer. Some animals remain as late as November, but the majority migrate south to temperate or tropical waters in the early fall.

Historically the primary grounds in the western North Atlantic were those in all the following areas: the Grand Banks just southeast of the southern Grand Banks from lat. 30 deg. to 40 deg.N and long. 35 deg. to 55 deg.W, off the Carolinas, around the Bahamas, around many of the West Indies, and in the southwestern Caribbean.

Stranded Specimens

Stranded sperm whales should be easy to identify. The very narrow underslung jaw contains from 18 to 25 functional teeth, which fit into sockets in the upper jaw. The huge, distinctly box-shaped head and the position of the single blowhole to the left front of the head are unmistakable clues.

Medium-sized Whales With a Dorsal Fin

MINKE WHALE (B)

_Balaenoptera acutorostrata_ Lacepede 1804

Other Common Names

Little piked whale, lesser rorqual, little firmer, sharp-headed finner, grampus (Newfoundland), gibord (Quebec).

Description

Minke whales are the smallest baleen whale species in the northern hemisphere, reaching maximum lengths of just over 30 feet (9.1 m). One of the most distinctive features of this species is an extremely narrow, pointed, distinctly triangular rostrum with a single head ridge, similar to but much sharper than that of the fin whale (hence the common name "sharp-headed finner"). Minke whales have a tall, falcate dorsal fin located in the latter third of the back, in about the same position as that of the sei whale, which often becomes visible simultaneously with the low, usually inconspicuous blow.

Minke whales are black to dark gray on the back and white on the belly and on the underside of the flippers. Portions of the underside of the flukes may be steel bluish gray. They have a diagonal band of white on each flipper, the extent and orientation of which varies individually.

Like the fin whale, minke whales (at least from the Pacific) sometimes have a chevron on the back behind the head and often have two regions of lightish-gray coloration on each side--one just above and behind the flippers; another just in front of and below the dorsal fin. These patches may be quite conspicuous on some animals, indetectable on others. These markings may also be present on Atlantic specimens, though they have not yet been documented. The baleen, which may be visible from close range when the animal is feeding, is mostly yellowish white with fine white bristles. The posterior plates (up to half) may be brown to black.

Natural History Notes

Minke whales are frequently found as single animals, pairs, or trios, though they may congregate in areas of food concentration in the northern seas during the spring and summer. They are more likely to be seen up close than their larger cousins--the blue, fin, and sei whales--because they often closely approach boats, particularly stationary boats, as if curious about them.

Minke whales may also approach very close to shore and often enter bays, inlets, and estuaries.

Like fin whales, they often arch the tail stock high into the air when beginning a long dive. However, they do not raise the flukes above the surface when beginning a dive.

Minke whales feed primarily on small shoal fish (herring, cod, pollack, and capelin).

Minkes sometimes breach, leaping completely clear of the water and entering smoothly, head first, or with a substantial splash like humpback whales.

May Be Confused With