Humpback Whale

## Description

The humpback whale (Megaptera novaeangliae ) is a species of baleen whale. It is a rorqual; a member of the family Balaenopteridae. Adults range in length from 14–17 m (46–56 ft) and weigh up to 40 metric tons (44 short tons). The humpback has a distinctive body shape, with long pectoral fins and a knobbly head. It is known for breaching and other distinctive surface behaviors, making it popular with whale watchers. Males produce a complex song typically lasting 4 to 33 minutes.

Found in oceans and seas around the world, humpback whales 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. Their diet consists mostly of krill and small fish. Unique among large whales, humpbacks use bubbles to catch prey. They are promiscuous breeders, with both sexes having multiple partners. Orcas are the main natural predators of humpback whales.

Like other large whales, the humpback was a target for the whaling industry. Humans once hunted the species to the brink of extinction; its population fell to around 5,000 by the 1960s. While numbers have partially recovered to some 135,000 animals worldwide, entanglement in fishing gear, collisions with ships, and noise pollution continue to affect the species.

## Appearance

The Humpback whale is among the biggest and the most easily recognized of the whale species. They are distinguished from other whales because of their large flippers, which are almost one-third the length of their body, and a hump on their backs. Their color ranges from gray to black, with white markings on their belly. These markings can be compared to fingerprints, different for every whale, and they allow researchers to identify individuals.

## Distribution

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 takes place, to feeding areas in Arctic waters.

## Behavior

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. 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.

## Diet

Humpback whales 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.

## Reproduction

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 for 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.

## Population

### Population threats

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.

### Population number

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).

## Fun Facts for Kids

Whales are mammals, and so they have hair, although they have very little.

The Humpback whale has this name due to the shape of the dorsal fin and the way it appears when it is diving.

Humpbacks communicate with loud, low-pitched moans, howls, and whines. They also communicate through visual cues and body language such as tail slapping, lunging, and breaching the water. This type of communication shows dominance, health, and youth during the mating season to demonstrate to others that they are fit, healthy, and good to mate with.

Humpbacks are famous for their water acrobatics. They can frequently be observed jumping out of the water, sometimes using their flukes to do so.

Calves can drink up to 600 liters of milk in a day, and within several months they develop a layer of blubber to help protect them from the cold.

Humpbacks have a diverse repertoire of feeding methods, including the bubble net technique; a group of whales dive up to 20 m (66 ft) below the surface and swim in a shrinking circle blowing air from their blowholes creating a vertical cylinder-ring of bubbles that captures the prey above them. Humpbacks use two main behaviors to create bubble-netting; upward spirals and double loops. After the nets are created, humpbacks swimming into them with their mouth gaping and ready to shallow.

Humpbacks are very friendly whales that interact with other cetaceans such as Bottlenose dolphins. They may play with dolphins and protect other animals such as seals and other whales from Killer whales.

Whales are air-breathing mammals who must surface to get the air they need. The stubby dorsal fin is visible soon after the blow (exhalation) when the whale surfaces, but disappears by the time the flukes emerge. Humpbacks have a 3 m (9.8 ft), heart-shaped bushy blow through the blowholes. They do not generally sleep at the surface, but they must continue to breathe. Possibly only half of their brain sleeps at one time, with one half managing the surface-blow-dive process without awakening the other half.