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Humpback Whale

Family: Balaenopteridae
Genus: Megaptera
species: novaeangliae

Interesting Facts & General Description


Like all Rorquals (Family Balaenopteridae, a family that includes the Blue whale, Fin whale, Bryde's whale, Sei whale and Minke whale) these long, slender whales are much more streamlined than other large whales. They have a pointed snout, paired blowholes, and a broad, flat rostrum (upper part of the head). The throat grooves, in addition to streamlining the shape of the whale, allow the throat area (called the cavum vent-rale) to expand tremendously during feeding. This allows the taking in of tons of food-laden water which is then discarded through their baleen plates leaving the fish or krill for swallowing. This efficient system enables the largest animals on earth to feed on some of the smallest. The baleen plates are broad and short, and the left and right rows are continuous anteriorly. The dorsal fin is falcate (curved). Humpbacks have grooves of varying length covering the region of the throat and chest. All Rorquals have been hunted and some still are, although they are now protected by all nations subscribing to the International Whaling Commission.

The Humpback Whale
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.

Adult males measure 40-48 ft (12.2-14.6 m), adult females measure 45-50 ft (13.7-15.2 m). They weigh 25 to 40 tons (22,680-36,287 kg). Their scientific name is Megaptera noveangliae. This means "giant wings", which refers to their large front flippers that can reach a length of 15 ft - about one-third of the animal's entire body length. 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. The shape and color pattern on the humpback whale's dorsal fin and fluke (tail) are as individual in each animal as are fingerprints in humans.

Humpbacks have become renowned for their various acrobatic displays. In fact, the common name "humpback" refers to the high arch of their backs when they dive. 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 ft (5.5 m) wide, is serrated and pointed at the tips. One of the humpback's more spectacular behaviors is the breach. Breaching is a true leap where a whale generates enough upward force with its powerful flukes to lift approximately two-thirds of its body out of the water. A breach may also involve a twisting motion, when the whale twists its body sideways as it reaches the height of the breach. Researchers are not certain why whales breach, but believe that it may be related to courtship or play activity. Some behaviors such as headlunging, which occurs when one whale thrusts its head forcefully towards another whale in a threatening manner, are believed to be aggressive behaviors meant to ward off competitors. Males display this behavior most often to gain access to females. Many other behaviors including fluke slaps, flipper slaps, and headslaps have also been characterized, although their apparent functions are unknown.

Communication
The "songs" of humpbacks are made up of complex vocal patterns. All whales within a given area and season seem to use the same songs. However, the songs appear to change from one breeding season to the next. Scientists believe that only male humpbacks sing. While the purpose of the songs is not known, many scientists think that males sing to attract mates, or to communicate among other males of the pod.

The Pod
A Pod refers to a social group of whales.

World Range & Habitat
Humpback whales are found in all of the world's oceans, although they generally prefer near shore and near-island habitats for both feeding and breeding. The current world population for the species is estimated to be between 5,000 and 7,500 individuals, and can be divided into groups based on the regions in which they live. One group found in the North Pacific in the waters off Alaska is estimated to consist of about 2,000 individuals. A large percentage of this population migrate to the Hawaiian islands during the winter months, November through May, each year. The round-trip distance they travel during this annual migration is approximately 6,000 miles, one of the longest migration distances of any animal species. During their stay in Hawaii, they do not feed, but rely upon energy stored in their blubber. Instead of feeding, the whales devote most of their time to mating and bearing their calves.

In the Atlantic Humpbacks migrate from Northern Ireland and Western Greenland to the West Indies (including the Gulf of Mexico).

In the Pacific they migrate generally from the Bering Sea to Southern Mexico as well. Another known small population migrates from their feeding grounds in Antarctic waters to their Tongan breeding grounds. These whales form part of an Antarctic feeding population south of New Zealand and Australia but little is known about the migration path of this small population and their movements between the Southwestern Pacific Islands. This "Tongan tribe" is even "more" special than other groups of humpbacks - it is the last group to be hunted, with the fewest survivors and is the least understood. Hunted until 1979 for their oil, meat and bone, scientists now pursue humpbacks for knowledge while travelers seek them for the thrill of their lives.

Feeding Behavior
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 in (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. They are known to concentrate the food by forming a bubble curtain, created by releasing air bubbles while swimming in a circle beneath the prey.