The humpback whalei s one of the rorquals, a family that includes the blue whale, fin whale, Bryde's whale, sei whale, and minke whale. Rorquals have two characteristics in common: dorsal fins on their backs, and ventral pleats running from the tip of the lower jaw back to the belly area. 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.
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.
In which oceans are Humpback Whales found?
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. Yet, 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.
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.
Since their feeding and nesting grounds are close to shore, and because they are slow swimmers, humpback whales are an easy target for hunters. Between 1905 and 1965, 28,000 humpback whales were killed. And though the International Whaling Commission (IWC) granted them worldwide protection in 1966, it is believed that they only number about 15,000-20,000 at present, or about 15-20% of the original population.
Note: Some information has been excerpted from the American Cetacean Society and World Wildlife Fund.