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Class:
Order:
Suborder:
Family:
Genus:
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Mammalia
Cetacea
Mysticeti
Balaenopteridae
Megaptera
Megaptera novaeangliae
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Humpbacks approach the Condor exhibiting "friendly" behavior common to this species!
PHYSICAL DESCRIPTION
The head of a humpback
whale is broad and rounded when viewed from above, but slim in profile.
The body is not as streamlined as other rorquals, but is quite round,
narrowing to a slender peduncle (tail stock). The top of the head and
lower jaw have rounded, bump-like knobs, each containing at least one
stiff hair. The purpose of these hairs is not known, though they may
provide the whale with a sense of "touch." There are between 20-35
ventral grooves which extend slightly beyond the navel.
COLOR
The body is black on the dorsal (upper) side, and
mottled black and white on the ventral (under) side. This color pattern
extends to the fluke. When the humpback whale "sounds" (goes into a
long or deep dive) it usually throws its fluke upward, exposing the
black and white patterned underside. This pattern is distinctive to
each whale. The flippers range from all white to all black.
FINS AND FLUKE
About 2/3 back on the body is an
irregularly shaped dorsal (top) fin. Its flippers are very long,
between 1/4 and 1/3 the length of its body, and have large knobs on the
leading edge. The fluke (tail), which can be 18 feet (5.5 m) wide, is
serrated and pointed at the tips.
LENGTH AND WEIGHT
Adult males measure 40-48 feet
(12.2-14.6 m), adult females measure 45-50 feet (13.7-15.2 m). They
weigh 25 to 40 tons (22,680-36,287 kg).
FEEDING
Humpback whales feed on krill, small shrimp-like
crustaceans, and various kinds of small fish. Each whale eats up to 1
and 1/2 tons (1,361 kg) of food a day. As a baleen whale, it has a
series of 270-400 fringed overlapping plates hanging from each side of
the upper jaw, where teeth might otherwise be located. These plates
consist of a fingernail-like material called keratin that frays out
into fine hairs on the ends inside the mouth near the tongue. The
plates are black and measure about 30 inches (76 cm) in length. During
feeding, large volumes of water and food can be taken into the mouth
because the pleated grooves in the throat expand. As the mouth closes
water is expelled through the baleen plates, which trap the food on the
inside near the tongue to be swallowed.
MATING AND BREEDING
Humpback whales reach sexual maturity
at 6-8 years of age or when males reach the length of 36 feet (11.6 m)
and females are 40 feet (12 m). Each female typically bears a calf
every 2-3 years and the gestation period is 12 months. A humpback whale
calf is between 10-15 feet (3-4.5 m) long at birth, and weighs up to 1
ton (907 kg). It nurses frequently on the mother's rich milk, which has
a 45% to 60% fat content. The calf is weaned to solid food when it is
about a year old.
DISTRIBUTION AND MIGRATION
Found in all the world's
oceans, most populations of humpback whales follow a regular migration
route, summering in temperate and polar waters for feeding, and
wintering in tropical waters for mating and calving.
NATURAL HISTORY
At least 3 different species of barnacles
are commonly found on both the flippers and the body of the humpback
whale. It is also home for a species of whale lice, Cyamus boopis.
Humpback whales are active, acrobatic whales. They can throw
themselves completely out of the water (breaching), and swim on their
backs with both flippers in the air. They also engage in "tail lobbing"
(raising their huge fluke out of the water and then slapping it on the
surface) and "flipper slapping" (using their flippers to slap the
water). It is possible that these behaviors are important in
communication between humpbacks.
Perhaps the most interesting behavior of humpback whales is their
"singing." Scientists have discovered that humpback whales sing long,
complex "songs." Whales in the North American Atlantic population sing
the same song, and all the whales in the North American Pacific
population sing the same song but the songs of each of these
populations and of those in other areas of the world are uniquely
different. A typical song lasts from 10-20 minutes, is repeated
continuously for hours at a time, and changes gradually from year to
year. It appears that all the singing whales are males and that the
songs may be a part of mating behavior.
STATUS
Because their feeding, mating, and calving grounds
are close to shore and because they are slow swimmers, the humpback
whales were an easy target for early whalers. Between 1905 and 1965,
28,000 humpback whales were killed. The International Whaling
Commission (IWC) gave them worldwide protection status in 1966. It is
believed they number about 15,000-20,000 at present, or about 15-20% of
the original population.
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