The humpback whale (Megaptera novaeangliae) is a species of baleen whale. One of the larger rorqual species, adults range in length from 12–16 metres (39–52 ft) and weigh approximately 36,000 kilograms (79,000 lb). The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head.
Humpback whales are well known for their long "pectoral" fins, which can be up to 15 feet (4.6 m) in length. Their scientific name, Megaptera novaeangliae, means "big-winged New Englander" as the New England population was the one best known to Europeans. These long fins give them increased maneuverability; they can be used to slow down or even go backwards.
These whales are found near coastlines, feeding on tiny shrimp-like krill, plankton, and small fish. Humpbacks migrate annually from summer feeding grounds near the poles to warmer winter breeding waters closer to the Equator. Mothers and their young swim close together, often touching one another with their flippers with what appear to be gestures of affection. Females nurse their calves for almost a year, though it takes far longer than that for a humpback whale to reach full adulthood. Calves do not stop growing until they are ten years old.
Humpbacks often congregate in groups of 20-30 to perhaps 100-200. These are among the most acrobatic and visible of whales and breach completely out of water in spectacular displays of strength. Humpbacks commonly slap their tail flukes or flippers on the water’s surface and occasionally lift their huge heads above water to peer about, a behavior known as "spyhopping." Tail slapping, breaching, and other such behaviors may serve in communication between the whales, possibly as warnings or a means of indicating location.
These gentle giants are famous for their singing abilities — belting out seductive ballads to attract mates or to challenge other would-be suitors. But they also have other talents. Their unique hunting skill, called bubblenet feeding, involves a group of humpbacks working together to capture schools of herring. Each whale has a particular role in the process: One whale swims in a circle while blowing bubbles under a school of herring. When the bubbles rise, the school of herring can not escape and form into a tight ball in the center. Other whales vocalize — grunting or screaming — to scare the herring to the surface. The whales then rise with their mouths wide open to capture large amounts of fish.
All members of the Order Cetacea (includes all whales, toothed and those using baleen ) are believed to have evolved from terrestrial hoofed mammals like cows, camels, and sheep some 45 million years ago - that's about 40 million years before humans! Recent comparisons of some milk protein genes (beta-casein and kappa-casein) have confirmed this relationship and have suggested that the closest land-bound living relative of whales may be the hippopotamus.
Humpback whales, Megaptera novaeangliae, are found in all of the world's oceans, although they generally prefer near shore and near-island habitats for both feeding and breeding. A recent world population for the species was estimated to be around 60,000 individuals (6,000 - 8,000 in the North Pacific, 12,000 in the North Atlantic, and approximately 40,000 in the Southern Hemisphere) or about 30-35% of their original population before whaling, 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.
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.
In the North Pacific, it is estimated that as many as 15,000 humpbacks existed prior to 1900. The population was truly decimated to fewer than 1,000 individuals before an international ban on commercial whaling was instituted in 1964. Today, the North Pacific population which returns to Hawaii in the winter months to breed, now numbers approximately 2,000. In spite of their recent strides towards recovery, humpbacks continue to be designated as an endangered species. Only the right whale, another species of baleen whale, is considered more endangered than the humpback in the North Pacific.
Humpback whales reach sexual maturity at 6-10 years of age or when males reach the length of 35 feet (11.6 m) and females reach 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.
Singing is virtually ubiquitous in the species’ breeding range in winter, and it has occasionally been recorded on the feeding grounds in summer and fall, as well as on migration. A song is produced only by single individuals, which are thought to be young but sexually mature males. Singers will sometimes sing continuously for hours or even days. There apparently are dialects, in that the song of the whales in one area differs to some extent from that heard in other areas. The songs vary from year to year, but, within each ocean, in each year the same new version of the song spreads throughout the different breeding groups.