Whales, Dolphins and Porpoises
Bryde’s Whale
Taxonomic Note: Some researchers recognize a similar animal for which they have given a separate species identification as Omura’s whale (Balaenoptera omura). Confirmation of this is speculative and if globally recognized, a separate species page will be added.
Bryde’s whales (often pronounced “brudas”) inhabit the tropical and subtropical oceans of the world and are naturally not as numerous as other rorqual species because food is less abundant in tropical waters. They are often confused with sei whales, but can be distinguished by the three prominent ridges present on their head. If close-up inspection is possible, the coarse gray baleen and ventral throat pleats extending to or beyond the navel are additional characteristics that identify Bryde’s whales. These whales are rather solitary in their habits, usually keeping their distance from each other even when there is a local abundance of food.
Oceanographers from the Galapagos Islands report a Bryde’s whale encounter in 1979, during which the whale approached a small sailboat closely enough to be touched and stroked for nearly 30 minutes.
Bryde’s whales were named after Captain Johan Bryde, who established South Africa’s first whaling station.
Physical Description: Bryde’s whales can be identified positively at close quarters by two secondary ridges on top of the rostrum, one on either side of the central ridge.
Color: They are dark gray dorsally, with a lighter color ventrally. They are occasionally dotted with small, white scars presumably caused by cookie-cutter shark bites. Some individuals possess a much lighter region on both sides forward of the dorsal fin. The right lower lip region is dark gray. A dark band runs across the stomach.
Fins and Flukes: The small dorsal fin (18 in, or 45 cm) is very falcate and situated at the extreme rear of the mid back region, although farther forward than that of some other whales. It often appears tattered or notched along the hind margin. Flippers are medium-sized and thin, very well developed and somewhat rounded at the tips. The flukes are almost identical to those of the blue whale: large, thin, pointed at the tips, and very well defined, with a definite median notch.
Length and Weight: Bryde’s whales reach 48 ft (14.6 m) and 22 tons (20,000 kg).
Throat Grooves: About 45 ventral throat grooves extend to the navel.
Baleen Plates: There approximately 300 plates on each side of the upper jaw, slate gray, with coarse dark-colored bristles up to 18 in (46 cm) in length.
Feeding: Schooling fish such as pilchard, sardine, and saury, as well as crustaceans and squid.
Breathing and Diving: There are several moderately high blows of about 11 ft (3.5 m) after a dive of 8 to 15 minutes. These are very fast and agile whales. Their pursuit of prey does not generally require deep dives, and they can be spotted by slicks of turbulence (tracks) at the surface that indicate they are swimming at a depth of 50 to 100 ft (15 to 30 m). The dorsal fin usually appears after the blowholes have submerged due to the steep angle of rising and diving in this relatively deep-diving species.
Mating and Breeding: The calf, 14 ft (4.3 m), 1 ton (900 kg), is born after an 11.5-month gestation. Males attain sexual maturity at 8 to 13 years when about 39 ft (12 m); females 7 to 8 years when about 43 ft (13 m).
Herding: Individually or in groups of up to 10. One large herd up of to 100 has been confirmed. Normally they are well dispersed.
Distribution: They are fond in the tropical and subtropical waters of the North Pacific, Central Pacific, South Atlantic, and Indian oceans between 40° north and 40° south latitudes.
Migration: Commonly believed not to migrate.
Natural History Notes: Bryde’s whales are believed to live to about 40 years. They are known to breach.
BRYDE'S WHALE DISTRIBUTION
Family: Balaenopteridae
With its long streamlined body, its gracefully pointed face, and its thin flukes, the fin whale might be considered to have classis rorqual features. Fin whales are the only cetacean asymetrically colored; the right side of the fin whale’s lower jaw and its right side baleen plates are white, while those of the left side are dark. They are fast and agile swimmers and work in pairs to round up and capture schools of fish. It is suspected that the white coloration on the right side of the whale’s face may play a role in feeding strategies. They are shy animals, compared to Bryde’s or minke whales, which are known for their tendency to approach boats and ships. Fin whales have been observed swimming with blue whales in some areas, including the Gulf of St. Lawrence. Fin whales seldom lift their flukes prior to lengthy dives, and they are not inclined to leap from the water, as do others of their family.
Physical Description: The body is long and slender. The rostrum closely resembles that of the blue whale but is thinner, more pointed, and always has a single central ridge. Fifty to 100 tactile hairs are found on the tips of the upper and lower jaws, with a distinctive clump of hairs at the tip of the lower jaw.
Color: Dark gray to brown dorsal and flank regions lighten to white ventral areas. Dark dorsal coloration extends farther down on the left side than the right, a feature unique among all cetaceans. Inside and outside of the right lower lip, and sometimes the upper lip as well, are yellow-white; the whalebone plates in that region are also yellow-white, while all other plates are yellow-gray. On most animals a gray-white chevron is located along the back and just behind the head.
Fins and Flukes: Prominent falcate dorsal fin 2 ft (60 cm) high is located far back of the dorsal ridge. Flippers are thin and pointed at the tips. The flukes are nearly identical to those of the blue whale: large, thin, pointed at the tips, very well defined, with a definite median notch.
Length and Weight: Fin whales reach 88 ft (27 m) and 80 tons (73,000 kg). Average length is 64.5 ft (20 m). Females are slightly larger than males. Fin whales in the Northern Hemisphere average about 5 ft (1.5 m) smaller at maturity than those of the Southern Hemisphere.
Throat Grooves: Fifty to 100 ventral grooves about 3 in (7.5 cm) apart extend slightly beyond the navel.
Baleen Plates: There are 350 to 360 baleen plates on each side of the upper jaw averaging 36 in (90 cm) in length, bluish-gray to white in color.
Feeding: Small crustaceans, North Atlantic populations also feed on capelin. North Pacific populations feed on small pelagic fish such as mackerel, tomcod, herring, saury, and even squid.
Breathing and Diving: Five to 6 breaths at intervals of several minutes preceding a dive lasting up to 15 minutes. A fin whale can dive to at least 755 ft (230 m). The blow, 15 to 20 ft (4.5 to 6 m), resembles an inverted cone. These whales seldom raise their flukes prior to longer dives.
Mating and Breeding: The calf, 21 ft (6.5 m) long, weighing 4 tons (3,600 kg), is born after an 11.5 month gestation. It is weaned after about 6 to 7 months when it has reached 39 ft (12 m). Sexual maturity is attained at 10 to 13 years when males are about 60 ft (18.5 m), females about 65 ft (19.8 m) long. Calving occurs at 2 to 3 year intervals. They are thought to be monogamous; much affectionate behavior is exhibited.
Herding: Often observed in groups exceeding 100, but normally singly to 10 animals.
Distribution: Fin whales inhabit all oceans, although they apparently avoid shallow waters and coastal regions. They frequent approximately the same waters as the blue whales. The largest population seems to be in Antarctic waters.
Migration: Apparently these whales feed in cold water regions during summer and return to warm waters for mating and breeding in winter. It has been noted that migration is irregular, perhaps because they are following food fish.
Natural History Notes: Fin whales are thought to live to between 75 and 100 years.
FIN WHALE DISTRIBUTION
Taxonomic Note: Some researcher believe that a blue whale population smaller in size and located in the Southern Hemisphere have its own separate species classification as a dwarf blue whale. When and if this is globally recognized among taxonomists, a separate species page will be added to this site.
It is scarcely possible to imagine the immense size of the blue whale. It is the largest known animal ever to inhabit the earth, exceeding even the great dinosaurs. Adult blue whales grow to more than 90 ft (24.7 m) in length and may weigh more than 150 tons (136,000 kg). The blue whale’s mouth can be 20 ft (6 m) long, its flippers 10 ft (3 m) long, and its flukes 15 ft (4.5 m) from tip to tip. Its heart is the size of a Volkswagen Beetle and pumps 10.7 tons (9,700 kg) of blood throughout the massive body in vessels so large that a human could crawl through the aorta. The blue whale’s brain exceeds 15 lb (7 kg) and its stomach is large enough to hold over 2 tons (1,800 kg) of krill, the largest species of which, Euphausia superba, reaches only 2 in (5 cm) in length. A full-grown adult blue whale requires 2 tons (1,800 kg) of food each day to maintain its metabolic level. For all its size, the blue whale is an agile animal, and can maneuver well in close quarters.
Blue whales are an endangered species, having been hunted extensively over many decades. However, small populations exist in several regions of the world, with the largest population off the west coast of North America.
Physical Description: Very broad body. The rostrum, like a broad, pointed arch when seen from above, has one large ridge extending from the tip to the blowholes, and, occasionally, two very small and inconspicuous ridges, one on each side of the large central ridge. The region around and including the blowhole is raised above the dorsal region.
Color: The overall color is blue-gray, mottled with gray-white. Accumulated cold-water diatoms produce a yellow ventral region on some animals, giving the species its principal alternate and seldom-used name of “sulphurbottom”.
Fins and Flukes: Extremely small, ordinarily falcate dorsal fin is located three-quarters of the way down the body; it appears at the termination point of a lengthy dorsal ridge. Long, thin flippers are well developed with a curvature along the leading margins, a feature unique among the rorqual whales. The flukes are relatively small, slightly rounded at their tips, with a median notch.
Length and Weight: The largest blue whale captured reportedly measured 110 ft. (33.5 m), although the average pre-whaling, full-grown adult more likely measured 85 to 90 ft (26 to 27.5 m) in length. Large blue whales have been so severely reduced in numbers through commercial whaling that the average size today is between 75 and 80 ft (23 to 24.5 m). Although the largest blues at one time may have exceeded 150 tons (136,000 kg), today’s average is about 110 tons (100,000 kg).
Throat Grooves: More than 40 ventral grooves extending to the navel.
Baleen Plates: More than 300 baleen plates line each side of the upper jaw. Usually they are all black, but photographs confirm occasional lighter coloration.
Feeding: Small euphausids in Southern Hemisphere; euphausids, other crustaceans, and small schooling fish in Northern Hemisphere. The whales dive with mouth open, scooping in their prey. The throat distends with the entering water, and the prey is strained as the water passes out through the baleen.
Breathing and Diving: Twelve to 14 shallow dives at 10 to 20 second intervals are followed by a longer presumably deeper dive averaging 10 to 20 minutes, although it can last up to 50 minutes. Blues can dive to at least 350 ft (110 m). The blow produces a 30 ft (9 m) tall, slender, vertical spout similar to that of the humpback whale.
Mating and Breeding: Calves, 25 ft. (7.5 m), weighing 7.5 tons (6,800 kg) are born after an 11.25-month gestation period. A calf suckles about 100 gallons (380 liters) of milk, gaining more than 200 lb (90 kg) per day. At weaning after 7 months, the calf is approximately 53 ft (16 m) long and weighs about 23 tons (21,000 kg). Sexual maturity is attained at about 23 to 30 years, when males average 74 ft (22.5 m) and females average 78 ft (24 m). Calving occurs at intervals of 2 to 3 years.
Herding: Blue whales are fond individually or in groups of up to several dozen spread out over many miles. Pairs are very common.
Distribution: Small numbers of blue whales may be found in all oceans of the world.
Migration: Northern Hemisphere populations move north to polar regions in the spring; Southern Hemisphere populations move south to polar regions in autumn.
Natural History Notes: While reports of blue whales breaching are rare, whale observers Stanley Minasian, Richard Sears, Lloyd Parker and pilot Bill Riffe observed a series of spectacular breaches from the air 10 miles (16 km) northeast of Danzante Island in Mexico’s Sea of Cortez in March of 1983. Two blue whales were observed, one estimated at 70 ft (21 m) and a smaller animal estimated at 56 ft (17 m). The smaller animal breached five to eight times in succession, each time at a 45-degree angle, always landing on its stomach. The breaches reduced in intensity until finally only head slapping occurred, followed by normal breathing patterns. It has been suggested that blue whales live at least 60 years.
BLUE WHALE DISTRIBUTION
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