The Humpback whale (Megaptera novaeangliae) is a species of baleen whale. It is a rorqual; a member of the family Balaenopteridae. The Humpback whale is known for breaching and other distinctive surface behaviors, making it popular with whale watchers. Found in oceans and seas around the world, these mysterious giants typically migrate up to 16,000 km (9,900 mi) each year. They feed in polar waters and migrate to tropical or subtropical waters to breed and give birth. Like other large whales, the Humpback whale was a target for the whaling industry and humans once hunted the species to the brink of extinction.
Humpback whales are bulky and have thin rostrums and proportionally long flippers, each around one-third of its body length. They have a short dorsal fin that varies from nearly non-existent to somewhat long and curved. As a rorqual, Humpback whales have grooves between the tip of the lower jaw and the navel. They are relatively few in number in this species, ranging from 14-35. The mouth is lined with baleen plates, which number 270-400 for both sides. Unique among large whales, Humpback whales have bumps or tubercles on the head and front edge of the flippers; their tail flukes have jagged trailing edges. The tubercles on the head are 5-10 cm (2-3.9 in) thick at the base and poke up to 6.5 cm (2.6 in). They are mostly hollow in the center, often containing at least one fragile hair that erupts 1-3 cm (0.4-1.2 in) from the skin and is 0.1 mm (0.0039 in) thick. The tubercles develop early in the womb and may have a sensory function as they are rich in nerves. The dorsal or upper side of Humpback whales is generally black; the ventral or underside has various levels of black and white coloration. Whales in the southern hemisphere tend to have more white pigmentation. The flippers can vary from all-white to white only on the undersurface. The varying color patterns and scars on the tail flukes distinguish individual animals.
Humpback whales inhabit all major oceans from sub-polar latitudes to the equator. There are four global populations of Humpbacks and they do not interact with each other: North Pacific, Atlantic, Southern Ocean, and Indian Ocean populations. Humpbacks live at the ocean's surface, both in shallow coastline waters and the open ocean. They migrate seasonally from the warm tropical waters where breeding and calving take place, to feeding areas in Arctic waters.
Typically, Humpback whales live alone or in small loose groups that can disband after a few hours. Groups may stay together longer in summer to forage and feed cooperatively. Longer-term relationships between pairs or small groups, lasting months or even years, have rarely been observed. Humpbacks sing more loudly than most other whales. Its songs can be heard over distances of several miles. The songs are sung by adult males, last up to 20 minutes, and then are repeated. Every year all the male whales sing the same song. While a whale sings, it floats in the water, its head down, and it is relatively motionless. The whale’s song purpose is not clear, though it may have a role in mating. Humpbacks make long journeys. During migration they travel slowly, socializing and resting along the way. Each humpback population has its own migratory route. They usually spend winter in warm, low-latitude, or tropical waters mating and giving birth, and during the rest of the year, they feed in cooler, higher-latitude polar waters.
Humpback whales are carnivores (piscivores, planktivores) and eat krill and small fish from schools such as haddock, herring, capelin, salmon, sand lance, pollock, and mackerel. They feed mostly during summer, living off their fat during winter.
Humpbacks are polygynous, and the males compete aggressively for mating access to females. They breed during winter in tropical waters. After a gestation of 11.5 months, one calf is born. Females must feed their calves around 45 kg of milk every day for 5-7 months until weaning, and calves may remain with their mothers for as much as a year. Mothers are affectionate and protective towards their calves, swimming nearby and often touching their babies with their flippers. Male humpbacks do not give parental support to calves. Mating usually takes place once every two years, though sometimes it occurs twice within three years. These whales are reproductively mature when they are 4-5 years old, and the birthing interval is 2 years.
Humpbacks are vulnerable to changes in the marine environment and also are threatened by water and noise pollution and the potential changes to fish stocks due to climate change. They may be harmed by collisions with ships, overfishing, and getting tangled in fishing gear. Offshore gas and oil development is also a threat to this species.
According to the IUCN Red List, the total Humpback whale population size is around 60,000 animals, including estimates for specific populations: North Atlantic - around 10,752 animals; North Pacific - 18,302 animals and 36,600 whales in the southern hemisphere. The number of humpback whales is increasing today and this species is classified as Least Concern (LC).