Description 
The Humpback Whale is one of the larger cetaceans, typically reaching lengths of 13 m for males and 14 m for females, and weighing 25 to 40 tonnes. It is a rorqual whale, a group of whales characterized by pleated grooves in the skin of the neck that allow the throat to expand during the intake of huge amounts of water during feeding, and the presence of a dorsal fin.

The body of the Humpback Whale is black on the dorsal side, and mottled black and white on the ventral side. This colour pattern extends to the fluke (tail), where the distinctive markings are unique and allow for the identification of each individual whale. The genus of the Humpback Whale, Megaptera, means huge wings, and refers to its flippers. They can be up to one-third of the whale’s body length, and are the largest flippers of any whale. The head is broad and rounded when viewed from above, with small, round bumps (called knobs or tubercles) edging the jaws.

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 have the tendency to raise their tail flukes above the surface when they dive.

Canadian Distribution of the Killer Whale (shown in red) 1,2 Distribution is approximate and not intended for legal use. 1Author: Canadian Wildlife Service, 2004 2Data Sources: The main source of information and data is the COSEWIC Status Report. In many cases additional data sources were used; a complete list will be available in the future.

Humpback Whales are found in tropical, temperate and sub-polar waters worldwide. In Canada, Humpbacks are found on both the east and west coasts, and belong to separate populations. The range of the Western North Atlantic population of Humpback Whales extends north to Labrador. This population was assessed by COSEWIC in 2003 and designated Not at Risk. The range of the North Pacific population extends along the full length of the west coast of British Columbia to northwestern Alaska.

The most recent population estimate for the North Pacific Humpback Whale, based on data from 1992 to 1993, is 6010 individuals. This is recognized as an underestimate; the true abundance may be closer to 8000 individuals. No estimates are available for the number of Humpbacks in the waters off the coast of British Columbia, but they are probably in the hundreds. Other more recent studies show localized increases in the number of Humpback Whales off Hawaii and California, and the overall population is considered to be growing.

Habitat 
Humpback Whales migrate seasonally between high-latitude feeding areas in summer and low-latitude breeding and calving areas in winter. Canadian waters are used primarily for feeding.

Biology 
Humpbacks travel in large, loose groups. Most associations between humpbacks are temporary, lasting at most a few days. The exception is the strong and lasting bond between mother and calves.

Humpback Whales become sexually mature at around five years of age but are not fully grown until they are about 10 years old. A female that mates one year on the winter breeding grounds will migrate to spend the summer feeding in colder waters, and then return to the breeding grounds to give birth. It is possible for a female to become pregnant again the following winter, but most have calves every two to three years.

At birth, a calf is just over 4 m long, and weighs about 1 tonne. It immediately starts feeding on its mother's rich milk, and quickly puts on weight. After about 10 months, when it has grown to around 8 m long, the calf is weaned. The mother is then no longer involved in its upbringing, though mothers and their offspring are sometimes seen together in later years on feeding grounds.

Humpback Whales feed on krill (shrimp-like crustaceans) and small schooling fish such as herring and mackerel. Humpbacks sometimes engage in social hunting, in which several whales encircle a school of fish and blow bubbles that form a “net” around the fish. The fish cluster tightly inside these nets, and all the whales have to do is to swim through with their mouths open.

One of the best-known features of Humpback Whales is their singing. The males sing the longest and most complex songs in the animal kingdom. The songs are long, varied, complex, eerie, and beautiful, including recognizable sequences of squeaks, grunts, and other sounds. The songs have the largest range of frequencies used by whales, ranging from 20 to 9000 Hertz. They sing the complex songs only in warm waters, perhaps for the purpose of attracting a mate. In cold waters, they make rougher sounds, scrapes and groans, perhaps to locate large masses of krill.

All the male whales in a population will sing the same song; it evolves over time as new sounds are added and old ones discarded. Different populations will sing different songs. For instance, whales in the North Atlantic will sing a very different song from those in the Pacific. The songs may travel for hundreds or even thousands of miles through the water.

Threats 
Population levels of the Humpback Whale were drastically reduced by commercial whaling. They are now recovering, but Humpbacks are still subjected to a variety of potential threats, mostly related to human activities. They may become entangled in fishing nets, be exposed to noise and chemical pollution, and suffer from habitat destruction. Overfishing may result in a reduction of their prey. A problem that has arisen in recent years is collisions of whales with ships. As ships get bigger and faster, it becomes harder for the whales to get out of the way. Many shipping lanes cross migration and feeding areas, making the risk of collision more likely.

Protection 
The Humpback Whale, North Pacific population, is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

Within Canada, management of Humpback Whales falls under the responsibility of the Department of Fisheries and Oceans. It is forbidden to disturb a marine mammal except under the authority of the Marine Mammal Regulations.

Other Protection or Status 
Commercial harvesting of Humpback Whales has been banned by the International Whaling Commission in the North Pacific since 1965.

Humpback Whales are also listed in Appendix 1 of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which sets controls on the international trade and movement of species that have been, or may be, threatened due to commercial exploitation.