Physical Attributes of Humpback Whales, Megaptera novaeangliae

Humpback whales reach lengths of up to 50 feet (over 15 meters) with the female being slightly larger than the male on average. They weigh an average of 40 tons (36 metric tons or 80,000 pounds). Their flukes span 12 to 15 feet (4 to 5 meters) and their pectoral fins can reach a length of 15 feet (almost 5 meters). These long pectoral fins give rise to the scientific name, Megaptera novaeangliae, which translates into "long-winged New Englander." Humpback calves are 12 to 15 feet (4 to 5 meters) long when they are born and weigh approximately 3,000 pounds (1.4 metric tons).

Identification of Individual Humpback Whales

Humpback whales are easily identified by the coloration or pigmentation of the ventral (underneath) side of the tail (fluke). Each animal has a unique pattern of black and white markings which are analagous to human fingerprints. Using these "fluke prints," researchers are beginning to unlock valuable clues about migration, stock exchange, and social association which may help us not only understand these animals but help to conserve them.

Migration of North Pacific Humpback Whales

North Pacific humpbacks migrate thousands of miles to meet their basic needs (food and reproduction). Alaskan waters, which are rich in food, are too cold for the survival of the virtually blubberless newborn calves. On the other hand, warm tropical waters, which are ideal for calving, lack adequate food resources for the humpback. For the most part, humpbacks do not eat when they are in Hawaii, although a few instances of opportunistic feeding have been observed.

Distribution of Humpback Whales

The distribution of the humpback whale is nearly worldwide. The current global population has been roughly estimated at 15,000 animals, which is less than 10% of their pre-whaling population. For this reason, they have been designated as an endangered species. The North Pacific stock consists of an estimated 6,000 whales, of which around 66% winter in Hawaiian waters.

Feeding of North Pacific Humpback Whales

Humpback whales eat a varied diet in Alaska. They are particularly "fond" of small schooling fishes, such as herring, sand lance, capelin, mackeral, etc., and krill (a collective term for shrimp-like crustaceans). They typically lunge after their food, although they also employ an ingenious strategy of creating bubblenets to trap their food just below the surface. After taking food and water into their mouths, humpbacks strain or filter the water through their baleen plates trapping food in their mouths. It has been estimated that a humpback consumes nearly a ton of food a day while in Alaska.

Song and Communication

Humpback whales are also perhaps best known for their vocalizations. Throughout the year, humpbacks emit social sounds which serve as a means of communication. But the most striking sound of the humpback is its song, which occurs most notably during the winter season. The song consists of a complex array of tones and frequencies, which constantly evolve throughout the winter calving season. Incredibly, humpbacks throughout the North Pacific sing the same version of the song during any given year. Researchers believe that only males sing and that the song serves some form of reproduction function since it only occurs most often when the whales are on their breeding grounds.