click for previous page

40 Marine Mammals of the World

2.3 SUBORDER MYSTICETI - Baleen Whales

MYSTICETI

There are 4 families of baleen whales. Mysticetes are universally large (with females growing larger than
males); the smallest is the pygmy right whale (c 7 m long), and the largest is the blue whale (the largest
animal ever to live, up to 33 m or more in length and 160 t in weight). The baleen whales have a double
blowhole, a symmetrical skull, and a sternum consisting of a single bone. In the mouth there is baleen (stiff
plates of keratin), instead of teeth. Baleen whales are batch feeders, taking in great quantities of water in a
single gulp, and then using the fringes on their baleen plates to filter small schooling fish or invertebrates
from the water. Nearly all mysticetes make long-range seasonal migrations.

2.3.1 Guide to Families of Baleen Whales

BALAENIDAE Right and Bowhead Whales (3 species in 2 genera) p. 42

llll
The right and bowhead whales are large and chunky,
with heads that comprise up to one-third of their body
length. They lack a dorsal fin or any trace of a dorsal
ridge. Overall, they tend to be far less streamlined than
other baleen whales. Right and bowhead whales have
developed a relatively passive skim-feeding technique,
and tend to be slower than other whales. The baleen
plates are the longest and have the finest fringes of the
4 mysticete families. Viewed in profile, the mouthline is
extremely arched and the skull profile is highly convex;
all 7 neck vertebrae are fused together. Fig. 140 Balaenidae

NEOBALAENIDAE Pygmy Right Whale (1 species in 1 genus) p. 48

The single species in this family, the pygmy right whale

of the Southern Hemisphere, is poorly known. Although
it is in some ways intermediate between the Balaenop-
teridae and Balaenidae, the pygmy right whale is more
closely related to the Balaenidae. Much smaller than
the right and bowhead whales (< 7 m), it is slender, with
a moderately arched mouthline. The head represents
only about one-quarter of the total length, and there is a
short falcate dorsal fin set behind midback. There is also
a pair of shallow throat grooves. The skull is also
somewhat intermediate; the rostrum is moderately
arched (reminiscent of balaenids), but is much wider at
its base (reminiscent of balaenopterids). Fig. 141 Neobalaenidae
Cetacea - Mysticeti 41

BALAENOPTERIDAE Rorquals (6 species in 2 genera) p. 50

This family contains the largest animals ever to live; all

balaenopterids have adult body lengths of over 7 m, and
some are much larger. The rorquals are streamlined
animals (the humpback whale somewhat less so than
the others), with a series of long pleats extending from
the snout tip to as far back as the navel on the ventral
surface. Balaenopterids are fast and active lunge feed-
ers; their morphology allows them to open their jaws very
widely and distend their throats to take in huge mouthfuls
of water during feeding. The baleen plates are of mod-
erate length and fringe fineness. Density and fringe
diameter vary among species, and along with plate
number and width to length ratio, are diagnostic charac-
ters. Rorquals have dorsal fins (varying in size and
shape) set behind the midpoint of the back. The upper
jaw has a relatively flat profile, a feature reflecting the
structure of the skull. Within a given feature, differences
among balaenopterids are often subtle variations on a
theme, rather than class distinctions. Therefore, infor-
mation on many features may be needed to distinguish Fig. 142 Balaenopteridae
among them and reliance on a single character for
identification is discouraged.

( ESCHRICHTIIDAE Gray Whale (1 species in 1 genus) p. 62

The gray whale was once present in both the Atlantic

and Pacific oceans, but has been exterminated in the
North Atlantic in the last few hundred years. This mono-
typic family is in some ways intermediate between the
Balaenidae and the Balaenopteridae. The gray whale is
stocky and has an arched jaw, but neither of these
characters is as pronounced as in the right whales. Gray
whales are slow-moving coastal animals that suck prey
from the bottom sediments. Gray whales have the short-
est and coarsest baleen of all species, a feature that
probably reflects both the size of their prey and their
tendency to take in gravel, sand, and other debris during
feeding. There are 2 to 5 short throat creases, a dorsal
hump followed by a series of knobs or knuckles along
the dorsal surface of the tail stock, and only 4 digits in Fig. 143 Eschrichtiidae
the flipper.
42 Marine Mammals of the World

2.3.2 FAO Species Identification Sheets

Eubalaena glacialis (Müller, 1776) BAL Eub 1 EUG

FAO Names: En - Northern right whale; Fr - Baleine de Biscaye; Sp - Ballena franca,

Fig. 144 Eubalaena glacialis

Distinctive Characteristics: The northern right

whale is one of the stockiest of all whales. It has
a massive head that can be up to nearly one-third
of its body length. The jawline is arched and the
upper jaw is very narrow in dorsal view. The
flippers are broad and tend to be more fan-shaped
than the pointed flippers of most other cetaceans,
There is no dorsal fin or dorsal ridge on the broad DORSAL VIEW

back. The flukes are very wide and smoothly

tapered, with a smooth trailing edge and a deep
notch.
Most right whales are predominantly black, but
there may be large white splotches of varying
extent on the belly and chin. The head is covered
with callosities, areas of roughened skin to which
whale lice and sometimes barnacles attach. The
largest of these callosities, on the top of the ros-
trum, is called the bonnet.
VENTRAL VIEW
The widely separated blowholes produce a V-
shaped blow up to 5 m high. Inside the mouth are
200 to 270 long thin baleen plates. which mav
reach nearly 3 m in length. They are brownish
grey to black in colour. The fringes of these plates
are very fine, reflecting the small prey taken by this
species.

LATERAL VIEW Fig. 145 Skull

Cetacea - Mysticeti - Balaenidae 43

Fig. 146 Surface - blow - dive profile

Can be confused with: In the northern extremes of their range, especially in the Bering and Okhotsk seas,
northern right whales may be confused with bowhead whales (p. 46). Bowhead whales lack callosities and
right whales have white patches only on the belly.
Size: Adults range in length to 17 m, but may occasionally reach 18 m. Females are larger than males.
Newborns are 4.5 to 6 m long. Adults may reach weights of 80 to 100 t.
Geographical Distribution: Right whales primarily inhabit temperate and subpolar waters. Northern right
whales are now extremely rare in the North Pacific and little is known of their current distribution there. The
2 North Atlantic populations are presumably isolated from each other, and the eastern stock is thought to be
near extinction. Calving and feeding areas throughout the world are most often in shallow nearshore regions.

* Extralimital record Fig. 147

Biology and Behaviour: Right whales are mostly seen in groups of less than 12 (most often singles or
pairs). Larger groups may form on feeding or breeding grounds. They can be aerially active and generally
raise their flukes before a deep dive. The mating system appears to involve sperm competition (males
competing to inseminate females, not so much by physical aggression, as by delivering large loads of sperm,
thereby displacing that of other males). Young are born in winter and spring in tropical or subtropical breeding
areas. Right whales feed on copepods and other small invertebrates, generally by slowly skimming through
patches of concentrated prey at or near the surface.
Exploitation: The right whales were the first targets of commercial whaling, starting in the eleventh century.
They were sought after because of their thick blubber layer (and thus high yield of oil), long flexible baleen
(used for many of the same purposes as plastic is today), slow swimming speeds, and tendency to float when
killed. North Pacific right whales were depleted to near extinction by commercial whaling, the most recent
episodes of which occurred as “scientific whaling” about 20 years ago. Sightings today are rare, apparently
the species is not recovering, even under full protection.
IUCN Status: Endangered.
44 Marine Mammals of the World

Eubalaena australis Desmoilins, 1822 BAL Eub 2 EUA

FAO Names: En - Southern right whale: Fr - Baleine australe; Sp - Ballena franca austral.

Fig. 148 Eubalaena australis

Distinctive Characteristics: These stocky

whales have extremely large heads, which can be
over one-fourth of the body length. The mouthline
is bowed and the rostrum is arched and very
narrow when viewed from above. As is true for
right and bowhead whales in general, there is no
trace of a dorsal fin or ridge in the southern right
whale. The flippers are fan-shaped, and the flukes
are broad with smooth contours. All right whales
have callosities on their heads, the largest of
which is called the bonnet. These callosity pat-
terns are individually distinctive and have been
used by researchers in many areas to identify
individuals.
DORSAL VIEW
Southern right whales are largely black, but some
have white patches of variable shape and size on
the belly and sometimes on the back. Colour
variants have been noted; these include blue-
black, light brown, and nearly white individuals. In
addition to those on the callosities, whale lice are
common in creases and folds on the bodies of
southern right whales.
The 200 to 270 baleen plates per side are narrow
and long, up to 3 m in length. The plates tend to
be dark grey to black (some can be nearly white)
and have fine grey to black fringes. The blow of
the southern right whale is relatively short and
V-shaped, making this species identifiable at a
distance, if seen from ahead or behind. LATERAL VIEW

Fig. 149
Cetacea - Mysticeti - Balaenidae 45

Can be confused with: The southern right whale is the only whale in its range with a smooth, finless back
and callosities; this should make misidentifications unlikely. From a distance the bushy, somewhat V-shaped
blows of humpback whales (p. 60) can be mistaken for those of right whales. At close range, the 2 species
are unmistakable.
Size: Southern right whale adults reach up to 17 m in length; females grow larger than males. These animals
can reach weights of at least 100 t. Newborn animals are 4.5 to 6 m.
Geographical Distribution: Southern right whales are distributed throughout the Southern Hemisphere,
from approximately 20ºS to 55ºS, although they have been observed as far south as 63ºS. In winter and
spring, the distribution is concentrated near coastlines. Major breeding areas are nearshore off southern
Australia, New Zealand, southern South America, and South Africa. A few right whales have been sighted
in Antarctic waters in summer.

* Possible extralimital record Fig. 150

Biology and Behaviour: Southern right whales have been well-studied on their winter breeding grounds,
especially at Peninsula Valdes, Argentina, and in South Africa. Researchers have used callosity patterns to
identify individuals on these grounds, and have learned much about the right whale’s behaviour, communi-
cation, and reproduction. Right whales often seem slow and lumbering, but can be surprisingly quick and
active. They often breach, and slap their flippers and flukes on the surface. Southern right whales often
raise their flukes on a dive.
Most of the breeding in Argentina takes place in August and September, but mating has been observed in
most months of the year. Male right whales have huge testes and long penises, 2 characteristics predicted
in species in which males compete for females primarily through sperm competition, rather than by direct
aggression.
Surface and subsurface skim feeding is the rule in this species. Southern right whales prey on copepods
and krill, apparently sometimes feeding near the bottom.
Exploitation: Southern right whale populations, like their northern counterparts, have been heavily depleted
by commercial whaling. Although not as endangered as the northern’ species, southern right whale
populations are still relatively small. Although fully protected by the IWC, there is probably still some hunting
for right whales. Despite the threats from whaling, entanglement in fishing gear, vessel collisions, and habitat
destruction, some southern right whale populations have s h o w n recent signs of recovery.
IUCN Status: Vulnerable.
46 Marine Mammals of the World

Balaena mysticetus Linnaeus, 1758 BAL Bala 1 BMY

FAO Names: En - Bowhead whale; Fr - Baleine du Groenland; Sp - Ballena de cabeza arqueada.

Fig. 151 Balaena mysticetus

Distinctive Characteristics: Bowhead whales

are extremely rotund overall, but often have a
distinct “neck” region. The head is large (up to
one-third of the body length); the upper jaw is
arched and narrow when viewed from above. The
mouthline is strongly bowed, and the eye is placed
just above the corner of the mouth. There is no
dorsal fin or ridge, and the back is very broad. The
flippers have blunt tips and the flukes are wide with
smooth contours. There is a large muscular bulge
(the stack) in the blowhole area.
DORSAL VIEW
Predominantly black in colour, bowheads have a
white patch at the front of the lower jaw; this patch
often has several dark grey to black spots, each
indicating the position of a chin hair. There is also
often a light grey to white band around the tail
stock, just in front of the flukes, and sometimes
other white or light grey areas on the body. The
white on the tail expands with age, and very large,
old bowheads may have an almost completely
white tail. Some lighter coloured bowheads are
occasionally seen. VENTRAL VIEW

Bowheads have the longest baleen plates of any

whale. The 250 to 350 plates in each side of the
jaw can reach lengths of 5.2 m; they have long,
fine fringes. The plates are dark grey to brownish
black, generally with slightly lighter fringes. As is
true for the closely related right whale, the blow is
V-shaped and bushy.

LATERAL VIEW Fig. 152 Skull

Cetacea - Mysticeti - Balaenidae 47

Fig. 153 Surface - blow - dive profile

Can be confused with: Gray whales (p. 62) use some of the same summer range as bowheads, but the
gray whale’s dorsal hump and knuckles, and differences in head and body shape, coloration, and behaviour
between the 2 species should make them distinguishable. Right whales (p. 42) might also overlap with
bowheads, but usually the 2 species are separated by their ecological preferences. The right whale’s
callosities and absence of light chin and peduncle patches will allow them to be distinguished from bowheads.
Size: Male bowhead whales range to 18 m in length, females to 20 m. Weights of large individuals have
been estimated at about 75 to 100 t. Calves are about 4 to 4.5 m long at birth.
Geographical Distribution: Bowheads are found only in arctic and subarctic regions. There are several
stocks in the North Atlantic Ocean, and the Bering, Beaufort, Chukchi, and Okhotsk seas. These animals
live much of their lives among the pack ice, migrating to the high arctic in summer, but retreating southward
in winter with the advancing ice edge.

* Extralimital record

Biology and Behaviour: Bowhead whales are usually seen in groups of 3 or fewer, but larger aggregations
form during the autumn migration and on the feeding grounds. Although often slow-moving, bowheads
breach and engage in other aerial behaviour. They frequently lift their flukes before a steep dive. Low
frequency calls are common, at least during migration.
Calves are born mainly in spring as whales migrate toward feeding grounds. The breeding system is thought
to be similar to that of the right whale, with males using a form of sperm competition. Small to medium-sized
invertebrates, especially krill and copepods, form the bulk of the bowhead’s diet. Bowheads skim feed at
the surface and feed in the water column.It has recently been suggested that they also feed near the bottom,
but probably do not directly ingest sediments as gray whales routinely do. During surface skim feeding,
coordinated group patterns have been observed, including whales feeding in echelon (V-shaped) formation.
Exploitation:Bowhead whales were heavily hunted for several centuries. Today they are partially protected
by the IWC. The current world population is still threatened by small-scale hunting by Alaskan, Canadian,
and Russian natives. In addition, there are various forms of habitat degradation, including disturbance from
oil and gas exploration and development activities.
IUCN Status: Vulnerable.
48 Marine Mammals of the World

Caperea marginata (Gray, 1846) NEOBA Cap 1 CPM

FAO Names: En - Pygmy right whale; Fr - Baleine pygmée; Sp - Ballena franca pigmea.

Fig. 155 Caperea marginata

Distinctive Characteristics: The pygmy right

whale is the only right whale with a dorsal fin. The
falcate fin is set about two-thirds of the way back
from the snout tip. This species is atypical of right
whales in other ways as well: it is rather slender,
resembling more the streamlined rorquals than the
chunky right and bowhead whales, and the head
is not large (less than one-quarter of the body
length). The pygmy right whale is like other right
whales in that it has an arched jawline; also the
lll
upper jaw curves downward toward the tip, al- DORSAL VIEW
though not as much as in balaenids. The flippers
are small and slender with rounded tips. There are
2 shallow throat creases, reminiscent of those in
gray whales.
The colour of the body is dark grey above, ranging
to white below. The flippers and flukes are dark
grey.
The baleen plates in this species number about
213 to 230 in each side of the upper jaw. They are
VENTRAL VIEW
up to 68 cm long and are said to be very flexible
and tough. The colour of the plates is yellowish
white.

LATERAL VIEW

Fig. 156 Skull

Cetacea - Mysticeti - Neobalaenidae 49

Can be confused with: This species can easily be confused with the minke whale (p. 58), but the differences
in head shape and the white flipper bands present in most populations of minke whales will allow
differentiation when specimens are seen clearly. From a distance, the back and dorsal fin could be confused
with those of a beaked whale; however, beaked whales have very different head shapes.
Size: The maximum recorded length for a male is 6.1 m and that for a female is 6.5 m. They reach weights
of at least 3 200 kg. At birth, pygmy right whales are about 2 m long.
Geographical Distribution: The pygmy right whale is known only from a few records in the Southern
Hemisphere, between the Antarctic Convergence (about 60ºS) and about 30ºS, in both coastal and oceanic
waters.

Fig. 157
Biology and Behaviour: This is the least known of all the baleen whales. Groups of up to 8 individuals have
been seen, but singles or pairs are most common. They are sometimes seen with other species of whales
and dolphins.
The inconspicuous small blow and quick shallow surfacings of the pygmy right whale makes it difficult to spot
and observe at sea. Sometimes, these animals bring their snout tips out of the water upon surfacing.
Very little is known about reproduction in this species, but the breeding season is thought to be protracted.
Pygmy right whales are known to feed on copepods.
Exploitation:, The smallest species of baleen whale, the pygmy right whale is also the only one that has not
been the target of large-scale commercial whaling. Some animals are incidentally captured in nets off South
Africa.
IUCN Status: Insufficiently known.
50 Marine Mammals of the World

Balaenoptera musculus (Linnaeus, 1758) BALAEN Bal 3 BLW

FAO Names: En - Blue whale: Fr - Rorqual bleu; Sp - Ballena azul.

Fig. 158 Balaenoptera musculus

Distinctive Characteristics: The blue whale is the

largest animal ever known; however, its size substan-
tially overlaps with that of adult fin and sei whales.
Like all rorquals, the blue whale is slender and
streamlined. The head is broad and U-shaped (like
a gothic arch) when viewed from above and relatively
flat when viewed from the side. Along the centre of
the rostrum, there is a single prominent ridge, which
ends in an impressive “splash guard” around the
blowholes. The flippers are long and pointed, and the
lllll
dorsal fin is relatively small, variably shaped, and
placed about three-quarters of the way back from the
DORSAL VIEW
snout tip. The broad flukes have a relatively straight
trailing edge and a prominent notch. In the Southern
Hemisphere and northern Indian Ocean, a subspe-
cies called the pygmy blue whale (B. m. brevicauda),
which is shorter and has a relatively larger head, has
been described. It is generally not possible to distin-
guish pygmy blue whales from other blue whales at
sea.
Blue whales are bluish grey dorsally and somewhat
lighter underneath. The head is uniformly blue, but
the back and sides are mottled. When viewed
through the water surface they may appear dappled
or uniformly light blue. There is light to extensive VENTRAL VIEW

mottling on the sides, back, and belly, generally in the

form of dark spots on a lighter surface, but sometimes
the reverse. A chevron, with the vertex behind the
blowholes, sometimes marks the transition of colora-
tion between the head and the body. Diatom films on
the surface may be seen as an orangish brown or
yellow tinge, which gave rise to the alternative name
“sulphur-bottom” whale.
On the throat, there are 55 to 88 long pleats extending
to or near the navel. The mouth contains 270 to 395 LATERAL VIEW

pairs of black, broad-based baleen plates, each less

than 1 m long. The blow is tall and slender, reaching Fig. 159 Skull
9 m or more in height.
click for next page