Hawaii State Mammal | ||||||||||||||||||
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Humpback Whale (common name)
Megaptera novaeangliae (scientific name) Overview
The humpback whale has a distinctive body shape, with unusually long pectoral fins and a knobbly head. The name "humpback" describes the motion the animal makes as it arches its back out of the water in preparation for a dive. The humpback is famous for its "songs" and its cooperative and complex feeding techniques. The introduction of the explosive harpoon in the late 19th century led to a sharp decline in its population. It is estimated that during the 20th century the global population of humpbacks decreased by over 90 percent. To prevent extinction, the International Whaling Commission introduced a ban on commercial humpback whaling in 1966. Hawaii designated the humpback whale as its official state marine mammal in 1979.
Close-upSTATUS
Official
ALSO KNOWN AS
Na kohola
PHYSICAL DETAILS
Humpbacks have a stocky body. Their heads and lower jaws are covered with knobs called tubercles, which are hair follicles. Humpbacks have 270 to 400 darkly colored baleen plates on each side of the mouth and 14 to 35 throat grooves that run from the chin to the navel. These grooves allow their throat to expand with the huge intake of water during filter feeding. Humpbacks have huge, mottled white flippers with rough edges that are up to one-third of their body length; these are the largest flippers of any whale. The deeply notched flukes (tail) are up to 12 feet (3.7 m) wide. Humpbacks have a small dorsal fin toward the flukes.
LIFESPAN
45 to 50 years
HABITAT
Humpbacks, which are found in all the major oceans, live at the surface of the ocean both in the open-ocean and shallow coastline waters. They migrate from warm tropical waters, where they breed and calve, to arctic waters, where they feed.
Conservation Status: Endangered. Since the whaling moratorium in 1966, stocks have partially recovered. Today, humpbacks are vulnerable to entanglement in fishing gear, collisions with ships, and noise pollution. There are at least 80,000 humpbacks worldwide.
BEHAVIOR
Humpbacks typically migrate up to 25,000 km each year, from their summer feeding grounds close to the poles to tropical or sub-tropical waters. They usually live alone or in small transient groups that assemble and break up over the course of a few hours. Males produce a complex whale song, which may play a role in mating. The humpback is an acrobatic animal, often breaching and slapping the water. These whales are famous for their diverse repertoire of feeding methods, including the bubble net feeding technique. Humpbacks have a 9.8 ft (3 m) heart-shaped to bushy blow. Their only non-human predator is the orca, which can kill young calves. Humpbacks feed only in summer, in polar waters.
DIET
Their diet consists mostly of krill and copepods in Australian and Antarctic waters and of small fish in the North Atlantic. During the winter, humpbacks fast and live off their fat reserves.
OFFSPRING
Breeding interval: 2–3 years
Birthing period: November–May Average litter size: 1 calf Size at birth: 4.3 m (14 ft) and about 2.5 tons TRIVIA
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Data Source: U.S. Fish and Wildlife Service
Author: World Trade Press
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24 Mart 2013 Pazar
Hawaii State Mammal
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