Humpback Whale

Humpback Whale

  • Scientific name: Megaptera novaeangliae
  • Size: Up to 20 metres in length and 40 tons at the largest.
  • IUCN Status
    • Global: LC (Least Concern)
    • Europe: LC (Least Concern)
  • Distribution: Extremely wide distribution, being found in all of the world’s major seas and oceans.
  • Feeds on: Humpback whales consume krill and small pelagic crustaceans, and will also eat fish, especially small shoaling fish species.
  • Description: Extremely large whale species. Body is thick and robust, with small dorsal fin. Mouth is downwards curving and is covered in lumps and bumps (which are called tubercles), as are the extremely long pectoral fins. Colour is usually black to dark greyish/blue, with white underside.

Humpback whales are a single species of very large baleen whale which has an extremely wide distribution. While they were once hunted by humans to near extinction, recent decades have seen the numbers of humpback whales make a significant improvement. Humpback whales are now economically important in a different way with whale watching tours becoming big business in parts of the world where humpback whales are present.

Distribution

Humpback Whale Distribution

Humpback whales have a worldwide distribution

Humpback whales are found on a worldwide basis with their long migratory patterns meaning that they are found in all of the major seas and oceans of the world. However, this migration means they are absent from enclosed and near-enclosed seas such as the Black Sea, the Baltic Sea and much of the Mediterranean. While humpback whales are not common in the waters around the British Isles they are present around certain parts of the UK, with the migratory patterns of this species meaning they are sighted off the coasts of western Ireland and the north and west coasts of Scotland. However, in 2013 humpback whales were seen off the coast of Norfolk – the first time a humpback whale had been spotted there since records began in the 1700s. The same whale is believed to have returned in 2014 and 2015.

Size and Lifespan

Humpback Whale Size Comparison

Size comparison between a humpback whale and the average human.

Humpback whales are very large once fully grown, and are amongst the larges whale species. Usually this species is around 12 to 15 metres long when fully grown and weigh around 25 tons. However they have been known to grow up to 20 metres at the absolute largest. Humpback whales are thought to have a natural lifespan of around fifty years.

Life Cycle and Behaviour

Unlike many other marine mammal species which are highly sociable and live in family groups for life humpback whales are mostly solitary creatures which spend the vast majority of their lives alone. They may spend time with other humpback whales occasionally, but this will only be briefly, and usually connected to either breeding or because a food source is abundant in a certain area. Like all whale species humpback whales create vocalisations, although with this species being mostly solitary the reason for vocalisation is not known, although it is theorised that it is connected to attracting mates.

Humpback Whale Breaching

Humpback whale breaching

Humpback whales also take part in other behaviour which humans are yet to understand. They will breach (jump out of the water) and often spin around as they are in the air. While this may be connected to feeding it is also beieved that it may be a type of communication, a method of freeing themselves of parasites or simply a form of playing. Similarly humpback whales can sometimes be observed slapping the surface of the water with their tail flukes or fins. Again the reason for this is unknown but it may be a way of communicating with other whales.

Most populations of humpback whales take part in long migrations of over 10,000 miles per year. They spend winter in the colder polar or sub-arctic regions where they will feed and then migrate – sometimes covering many thousands of miles to warmer summer waters where they will breed. During their migrations humpback whales do not feed as much as they live off the fat reserves which they have built up over the winter.

Feeding and Prey

Humpback whale diving

Animation of a humpback whale diving © Hersfold

Although they are a baleen species of whale, humpback whales feed on a wide variety of different food sources. They will consume krill and small pelagic crustaceans, but also eat small shoaling fish such as herring, capelin and sandeels. However, they are also known to feed on larger species with fairly large cod, haddock and pollock all being taken as well. Humpback whales will dive deep when feeding. When they are about to dive they will arch their back as they propel themselves downwards. It is this motion which gives this species its common name. Humpback whales take part in a method of trapping prey known as bubble feeding where whales will dive deep and swim in circles blowing bubbles. This will trap prey fish inside the circular bubble net and the humpback whales will then swim upwards with their mouths open allowing them to easily catch the preyfish which have been trapped inside.

Humpback whale bubble feeding

Humpback whale bubble feeding

Due to their very large size humpback whales are not preyed on by any species once they are fully grown, but humpback calves may be hunted and eaten by large predators such as killer whales and sharks.

Reproduction

Humpback whales are thought to be able to reproduce at the age of five or six. The gestation period is around one year and calves are several metres long when they are born. They feed on the mother’s high-fat milk and grow rapidly. While humpback whales are not sociable creatures the mothers do care for the young for the early part of their lives.

Other Facts

The unique marks on the pectoral and tail fins of humpback whales mean that each whale is individually identifiable and whales spotted on whale watching tours, or those observed by scientists, are often named. Famous humpback whales include Humphrey – a humpback whale which was rescued from swimming up the Sacramento River in California, and Migaloo, a completely white albino humpback whale found off the coast of Australia.

Reduction in Hunting and Increase in Whale Watching

Humpback whales have been hunted by humans since the 1600s with numbers of humpback whales being reduced massively on a worldwide basis once industrial whaling became common in the 1950s. By the 1960s the humpback whale was critically endangered and on the verge of being at danger of extinction. However, a worldwide ban on the hunting of this species came into force in 1966 and since then numbers have improved remarkably, with many populations of humpback whales now approaching pre-industrial whaling levels. While some isolated sub-populations of humpback whales are listed as threatened, overall the numbers of this species are seen as being in good condition, leading to the IUCN classing this species as one of Least Concern both globally and in the European regional assessment. The major threats to humpback whales today come from entanglements in fishing nets and disruption to this species caused by the powerful sonar and radar used by military vessels. However, these threats are not thought to cause enough damage to humpback whale numbers to significantly impact on the overall sustainability of the species.

Whale Watching Boston

People observing a humpback whale making a dive during a whale watching tour off the coast of Boston, Massachusetts.

Today whale-watching tours are big business around many parts of the world, with humpback whales being one of the main attractions due to their size and impressive dives. In US states such as Massachusetts and Hawaii whale-watching contributes considerably to the local economy.

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