The humpback whale (Megaptera novaeangliae) is a baleen whale. One of the larger rorqual species, adults range in length from and weigh approximately . The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the water. Males produce a complex whale song, which lasts for 10 to 20 minutes and is repeated for hours at a time. The purpose of the song is not yet clear, although it appears to have a role in mating.

Found in oceans and seas around the world, humpback whales typically migrate up to 25,000 kilometres each year. Humpbacks feed only in summer, in polar waters, and migrate to tropical or sub-tropical waters to breed and give birth in the winter. During the winter, humpbacks fast and live off their fat reserves. The species' diet consists mostly of krill and small fish. Humpbacks have a diverse repertoire of feeding methods, including the bubble net feeding technique.

Like other large whales, the humpback was and is a target for the whaling industry. Due to over-hunting, its population fell by an estimated 90% before a whaling moratorium was introduced in 1966. Stocks have since partially recovered; however, entanglement in fishing gear, collisions with ships, and noise pollution also remain concerns. There are at least 80,000 humpback whales worldwide. Once hunted to the brink of extinction, humpbacks are now sought by whale-watchers, particularly off parts of Australia, Canada, and the United States.

Taxonomy

A phylogenetic tree of animals related to the humpback whale

Humpback whales are rorquals (family Balaenopteridae), a family that includes the blue whale, the fin whale, the Bryde's whale, the Sei whale and the Minke whale. The rorquals are believed to have diverged from the other families of the suborder Mysticeti as long ago as the middle Miocene. However, it is not known when the members of these families diverged from each other.

Though clearly related to the giant whales of the genus Balaenoptera, the humpback has been the sole member of its genus since Gray's work in 1846. More recently though, DNA sequencing analysis has indicated the Humpback is more closely related to the Gray Whale (Eschrichtius robustus) and to certain rorquals, such as the Fin Whale (Balaenoptera physalus) than it is to other rorquals such as the minke whales. If further research confirms these relationships, it will be necessary to reclassify the rorquals.

The humpback whale was first identified as "baleine de la Nouvelle Angleterre" by Mathurin Jacques Brisson in his Regnum Animale of 1756. In 1781, Georg Heinrich Borowski described the species, converting Brisson's name to its Latin equivalent, Balaena novaeangliae. Early in the 19th century Lacépède shifted the humpback from the Balaenidae family, renaming it Balaenoptera jubartes. In 1846, John Edward Gray created the genus Megaptera, classifying the humpback as Megaptera longpinna, but in 1932, Remington Kellogg reverted the species names to use Borowski's novaeangliae. The common name is derived from the curving of their back when diving. The generic name Megaptera from the Greek mega-/μεγα- "giant" and ptera/πτερα "wing", refers to their large front flippers. The specific name means "New Englander" and was probably given by Brisson due the regular sightings of humpbacks off the coast of New England.

Description and lifecycle

Humpback whales can easily be identified by their stocky bodies with obvious humps and black dorsal coloring. The head and lower jaw are covered with knobs called tubercle, which are actually hair follicles and are characteristic of the species. The tail flukes, which are lifted high in some dive sequences, have wavy trailing edges. There are four global populations, all under study. North Pacific, Atlantic, and southern ocean humpbacks have distinct populations which complete a migratory round-trip each year. The Indian Ocean population does not migrate, stopped by that ocean's northern coastline.

The long black and white tail fin, which can be up to a third of body length, and the pectoral fins have unique patterns, which make individual whales identifiable. Several hypotheses attempt to explain the humpback's pectoral fins, which are proportionally the longest fins of any cetacean. The two most enduring mention the higher maneuverability afforded by long fins, and the usefulness of the increased surface area for temperature control when migrating between warm and cold climates. Humpbacks also have 'rete mirable' a heat exchanging system, which works similarly in humpbacks, sharks and other fish.

Humpbacks have 270 to 400 darkly coloured baleen plates on each side of the mouth. The plates measure from a mere in the front to approximately long in the back, behind the hinge. Ventral grooves run from the lower jaw to the umbilicus about halfway along the bottom of the whale. These grooves are less numerous (usually 16–20) and consequently more prominent than in other rorquals. The stubby dorsal fin is visible soon after the blow when the whale surfaces, but disappears by the time the flukes emerge. Humpbacks have a heart shaped to bushy blow, or exhalation of water through the blowholes. Early whalers also noted blows from humpback adults to be high. Whaling records reveal understanding of the species-specific shape and height of blows.

Newborn calves are roughly the length of their mother's head. A mother would have a newborn weighing in at . They are nursed by their mothers for approximately six months, then are sustained through a mixture of nursing and independent feeding for possibly six months more. Humpback milk is 50% fat and pink in color. Some calves have been observed alone after arrival in Alaskan waters.

Females reach sexual maturity at the age of five with full adult size being achieved a little later. Males reach sexual maturity at approximately 7 years of age. Whale lifespan estimates range from 30-40 years to 70-80 years.

Fully grown the males average , the females being slightly larger at , with a weight of ); the largest recorded specimen was long and had pectoral fins measuring each. The largest humpback on record, according to whaling records, was killed in the Caribbean. She was long, weighing nearly .

Females have a hemispherical lobe about in diameter in their genital region. This allows males and females to be distinguished from the underside, even though the male's penis usually remains hidden in the genital slit. Male whales have distinctive scars on heads and bodies, some resulting from battles over females.

Identification

The varying patterns on the humpback's tail flukes are sufficient to identify an individual. Unique visual identification is not currently possible in most cetacean species (other exceptions include Orcas and Right Whales), making the humpback a popular species for study. A study using data from 1973 to 1998 on whales in the North Atlantic gave researchers detailed information on gestation times, growth rates, and calving periods, as well as allowing more accurate population predictions by simulating the mark-release-recapture technique. A photographic catalogue of all known whales in the North Atlantic was developed over this period and is currently maintained by Wheelock College. Similar photographic identification projects have begun in the North Pacific by SPLASH (Structure of Populations, Levels of Abundance and Status of Humpbacks), and around the world. Another organization (Cascadia Research) headed by well-known researcher John Calambokidis, along with Dr. Robin Baird, joined with others from NOAA, hoping to prepare a public online catalog of more than 3500 fluke identification pictures.

Social structure and courtship

The humpback social structure is loose-knit. Usually, individuals live alone or in small transient groups that assemble and break up over the course of a few hours. Groups may stay together a little longer in summer in order to forage and feed cooperatively. Longer-term relationships between pairs or small groups, lasting months or even years, have rarely been observed. Recent studies extrapolate feeding bonds observed with many females in Alaskan waters over the last 10 years. It is possible some females may retain these bonds for a lifetime. The range of the humpback overlaps considerably with many other whale and dolphin species — (for instance, the Minke Whale). However, humpbacks rarely interact socially with them. Humpback calves have been observed in Hawaiian waters playing with bottlenose dolphin calves.

Courtship rituals take place during the winter months, when the whales migrate toward the equator from their summer feeding grounds closer to the poles. Competition is usually fierce, and unrelated males dubbed escorts by researcher Louis Herman frequently trail females as well as mother-calf dyads. Groups of two to twenty males typically gather around a single female and exhibit a variety of behaviors in order to establish dominance in what is known as a competitive group. Displays may last several hours. Competitive group size may ebb and flow as unsuccessful males retreat and others arrive to try their luck. Techniques used include breaching, spy-hopping, lob-tailing, tail-slapping, flipper-slapping, peduncle throws, charging and parrying. "Super pods" have been observed numbering more than 40 males, all vying for the same female. (M. Ferrari et al.)

Whale song is assumed to have an important role in mate selection; however, scientists remain unsure whether the song is used between males in order to establish identity and dominance, between a male and a female as a mating call, or a mixture of the two. All these vocal and physical techniques have also been observed while not in the presence of potential mates. This indicates that they are probably important as a more general communication tool. Recent studies show singing males attracting other males. Scientists hypothesize that the singing may be a way to keep migrating populations connected. (Ferrari, Nicklin, Darling, et al.) It has also been noted that the singing begins when the competition ends.

Feeding

Humpbacks feed only in summer and lives off fat reserves during winter. They feed only rarely and opportunistically while in their wintering waters. The humpback is an energetic feeder, taking krill and small schooling fish, such as herring (Clupea harengus), salmon, capelin (Mallotus villosus) and sand lance (Ammodytes americanus) as well as Mackerel (Scomber scombrus), pollock (Pollachius virens) and haddock (Melanogrammus aeglefinus) in the North Atlantic. Krill and Copepods have been recorded from Australian and Antarctic waters. Humpbacks hunt fish by direct attack or by stunning them by hitting the water with its pectoral fins or flukes. The humpback has the most diverse repertoire of feeding methods of all baleen whales. Its most inventive technique is known as bubble net feeding: a group of whales swims in a shrinking circle blowing bubbles below a school of prey. The shrinking ring of bubbles encircles the school and confines it in an ever-smaller cylinder. The whales then suddenly swim upward through the bubble net, mouths agape, swallowing thousands of fish in one gulp. This ring can begin at up to in diameter via the cooperation of a dozen animals. Some of the whales blow the bubbles, some dive deeper to drive fish toward the surface, and others herd other fish into the net by vocalizing. Humpbacks have been observed bubblenet feeding alone as well.

Humpback whales are preyed upon by Orcas. The result of these attacks is generally nothing more serious than some scarring of the skin, but it is likely that young calves are sometimes killed.

Reproduction

Females typically breed every two or three years. The gestation period is 11.5 months, yet some individuals can breed in two consecutive years. Humpback whales were thought to live 50–60 years, but new studies using the changes in amino acids behind eye lenses proved another baleen whale, the Bowhead, to be 211 years old. This was an animal taken by the Inuit off Alaska. More age studies are currently active.

Recent research on humpback mitochondrial DNA reveals that groups that live in proximity to each other may represent distinct breeding pools.

Song

Both male and female humpback whales produce sounds, however only the males produce the long, loud, complex "songs" for which the species is famous. Each song consists of several sounds in a low register that vary in amplitude and frequency, and typically lasts from 10 to 20 minutes. Humpbacks have been observed to sing continuously for more than 24 hours. Cetaceans have no vocal cords, so whales generate their song by forcing air through their massive nasal cavities.

Whales within a large area sing the same song. All of the humpbacks of the North Atlantic sing the same song, and those of the North Pacific sing a different song. Each population's song changes slowly over a period of years—never returning to the same sequence of notes.

Scientists are still unsure of the purpose of whale song. Only males sing, suggesting that the purpose of the songs is to attract females. However, many of the whales observed to approach a singer are other males, with the meeting resulting in conflict. Singing may therefore be a threat to other males. Some scientists have hypothesized that the song may serve an echolocative function. During the feeding season, humpbacks make altogether different vocalizations for herding fish into their bubble nets.

Population and distribution

The humpback whale is found in all the major oceans, in a wide band running from the Antarctic ice edge to 65° N latitude, though not in the eastern Mediterranean or the Baltic Sea. There are at least 80,000 humpback whales worldwide, with 18,000-20,000 in the North Pacific, about 12,000 in the North Atlantic, and over 50,000 in the Southern Hemisphere, down from a pre-whaling population of 125,000.

Humpbacks are migratory, spending summers in cooler, high-latitude waters, but mating and calving in tropical and subtropical waters. An exception to this rule is a population in the Arabian Sea, which remains in these tropical waters year-round. Annual migrations of up to are typical, making it one of the farthest-travelling of any mammalian species.

A 2007 study identified seven individual whales wintering off the Pacific coast of Costa Rica as those which had made a trip from the Antarctic of around . Identified by their unique tail patterns, these animals have made the longest documented migration by a mammal.

In Australia, two main migratory populations have been identified, off the west and east coast respectively. These two populations are distinct with only a few females in each generation crossing between the two groups.

Whaling

One of the first attempts to hunt the humpback whale was made by John Smith in 1614 off the coast of Maine. Opportunistic killing of the species is likely to have occurred long before, and it continued with increasing pace in the following centuries. By the 18th century, they had become a common target for whalers.

By the 19th century, many nations (the United States in particular), were hunting the animal heavily in the Atlantic Ocean, and to a lesser extent in the Indian and Pacific Oceans. It was, however, the introduction of the explosive harpoon in the late 19th century that allowed whalers to accelerate their take. This, along with hunting beginning in the Antarctic Ocean in 1904, led to a sharp decline in most whale populations.

It is estimated that during the 20th century at least 200,000 humpbacks were taken, reducing the global population by over 90%, with the population in the North Atlantic estimated to have dropped to as low as 700 individuals.

To prevent extinction, the International Whaling Commission introduced a ban on commercial humpback whaling in 1966. That ban is still in force. By that time the total population had been reduced to an estimated 5000 whales.

Prior to commercial whaling, population numbers could have reached 125,000. North Pacific kills alone are estimated at 28,000. The full toll is much higher. It is now known that the Soviet Union was deliberately under-recording its kills; the total Soviet humpback kill was reported at 2,820 whereas the true number is now believed to be over 48,000.

As of 2004, hunting of humpback whales is restricted to a few animals each year off the Caribbean island Bequia in the nation of St. Vincent and the Grenadines. The take is not believed to threaten the local population.

Japan had planned to kill 50 humpback whales in the 2007/08 season under its JARPA II research program in the Antarctic Ocean, starting in November 2007. The announcement sparked global protests.After a visit to Tokyo by the chairman of the IWC, asking the Japanese for their co-operation in sorting out the differences between pro- and anti-whaling nations on the Commission, the Japanese whaling fleet agreed that no humpback whales would be caught for the two years it would take for the IWC to reach a formal agreement.

Conservation

Internationally this species is considered "least concern" from a conservation standpoint as of 2008. This is an improvement from vulnerable status in the prior assessment. Most monitored stocks of humpback whales have rebounded well since the end of the commercial whaling era, such as the North Atlantic where stocks are now believed to be approaching pre-hunting levels. However, the species is considered endangered in some countries, including the United States. The United States initiated a status review of the species on August 12, 2009 and is seeking public comment on potential changes to the species listing under the U.S. Endangered Species Act. Comments must be received by October 13, 2009. Areas where population data is limited and the species may be at higher risk include the Arabian Sea, the western North Pacific Ocean, the west coast of Africa and parts of Oceania.

Today, individuals are vulnerable to collisions with ships, entanglement in fishing gear, and noise pollution. Like other cetaceans, humpbacks are sensitive to noise and can even be injured by it. In the 19th century, two humpback whales were found dead near sites of repeated oceanic sub-bottom blasting, with traumatic injuries and fractures in the ears.

Once hunted to the brink of extinction the humpback whale has made a dramatic comeback in the North Pacific Ocean. A study released May 22, 2008 estimates that the humpback whale population that hit a low of 1,500 whales before hunting was banned worldwide, has made a comeback to a population of between 18,000 and 20,000, or in other estimats, 60,000 or more.

The ingestion of saxitoxin, a Paralytic shellfish poisoning (PSP) from contaminated mackerel has been implicated in humpback whale deaths.

Some countries are creating action plans to protect the humpback; for example, in the United Kingdom, the humpback whale has been designated as a priority species under the national Biodiversity Action Plan, generating a set of actions to conserve the species. The sanctuary provided by National Parks such as Glacier Bay National Park and Preserve and Cape Hatteras National Seashore, among others, have also become a major factor in sustaining the populations of the species in those areas.

Although much was learned about the humpback from whaling, migratory patterns and social interactions of the species were not well understood until two studies by R. Chittleborough and W. H. Dawbin in the 1960s. Roger Payne and Scott McVay made further studies of the species in 1971. Their analysis of whale song led to worldwide media interest, and left an impression in the public mind that whales were highly intelligent species, contributing to the anti-whaling stance of many countries.

In August 2008, the IUCN changed the whale's status from Vulnerable to Least Concern, although two subpopulations remain endangered.

The United States is considering separately listing separate humpback populations, so that populations such as North Pacific humpbacks, which are estimated to number 12,000 animals, might be delisted. This is made difficult by humpback's extraordinary migrations, which can extend the 5,157 miles from Antartica to Costa Rica.

Whale-watching

Humpback whales are generally curious about objects in their environment. Some individuals, referred to as "friendlies", approach whale-watching boats closely, often staying under or near the boat for many minutes. Because humpbacks are often easily approachable, curious, easily identifiable as individuals, and display many behaviors, they have become the mainstay of whale-watching tourism in many locations around the world.

There are many commercial whale-watching operations on both the humpback's summer and winter ranges:

	North Atlantic	North Pacific	Southern Hemisphere
Summer	New England, Nova Scotia and Newfoundland, the northern St. Lawrence River, the Snaefellsnes peninsula in the west of Iceland	California, Alaska, Oregon, Washington, British Columbia	Antarctica
Winter	Samaná Province of the Dominican Republic, the Bay of Biscay France,	Hawaii, Baja, the Bahía de Banderas off Puerto Vallarta	Sydney, Byron Bay north of Sydney, Hervey Bay north of Brisbane, North and East of Cape Town, New Zealand, the Tongan islands,

As with other cetacean species, however, a mother whale is generally extremely protective of her infant, and places herself between any boat and her calf before moving quickly away from the vessel. Skilled tour operators avoid stressing the mother.

Famous humpbacks

Migaloo

A presumably albino humpback whale that travels up and down the east coast of Australia has become famous in the local media, on account of its extremely rare all-white appearance. Migaloo is the only known all-white humpback whale in the world. First sighted in 1991 and believed to be 3–5 years old at that time, Migaloo is a word for "white fellow" from one of the languages of the Indigenous Australians. Speculation about Migaloo's gender was resolved in October 2004 when researchers from Southern Cross University collected sloughed skin samples from Migaloo as he migrated past Lennox Head, and subsequent genetic analysis of the samples proved he is a male. Because of the intense interest, environmentalists feared that he was becoming distressed by the number of boats following him each day. In response, the Queensland and New South Wales governments introduce legislation each year to create a exclusion zone around the whale. Recent close up pictures have shown Migaloo to have skin cancer and/or skin cysts as a result of his lack of protection from the sun.

In 2006, a white calf was spotted with a normal humpback mother in Byron Bay, New South Wales.

Humphrey

One of the most notable humpback whales is Humphrey the whale, twice-rescued by The Marine Mammal Center and other concerned groups in California. In 1985, Humphrey swam into San Francisco Bay and then up the Sacramento River towards Rio Vista. Five years later, Humphrey returned and became stuck on a mudflat in San Francisco Bay immediately north of Sierra Point below the view of onlookers from the upper floors of the Dakin Building. He was pulled off the mudflat with a large cargo net and the help of the Coast Guard. Both times he was successfully guided back to the Pacific Ocean using a "sound net" in which people in a flotilla of boats made unpleasant noises behind the whale by banging on steel pipes, a Japanese fishing technique known as "oikami." At the same time, the attractive sounds of humpback whales preparing to feed were broadcast from a boat headed towards the open ocean. Since leaving the San Francisco Bay in 1990 Humphrey has been seen only once, at the Farallon Islands in 1991.

Delta and Dawn

A humpback whale mother and calf captivated the San Francisco Bay Area in May 2007. This pair appeared to have gotten lost on their Northern migration, swam into the bay and up the Sacramento River as far as the Port of Sacramento. First spotted on 13 May, the whales inspired intense news coverage and were named Delta and Dawn. Whale fans became worried as the whales, both injured with what were possibly cuts caused by boat propellers, continued their stay in the brackish waters, despite efforts to get them to return to the sea. Unexpectedly, on 20 May they headed back towards the bay, but they tarried near the Rio Vista bridge for 10 days. Finally, on Memorial Day weekend, they left Rio Vista, California; passing Tuesday night, 29 May, through the Golden Gate Bridge out to the Pacific Ocean.

Mister Splashy Pants

Mister Splashy Pants is a humpback in the south Pacific Ocean. It's being tracked with a satellite tag by Greenpeace as a part of its Great Whale Trail Expedition. The whale's name was chosen in an online poll that garnered attention from several websites, including Boing Boing and Reddit. The name "Mister Splashy Pants" received over 78% of the votes.

Colin

Colin was the name given to a presumably abandoned starving humpback calf that was discovered in August 2008 at Pittwater, north of Sydney, Australia. It attempted to suckle from moored boats to obtain food. Despite attempts to reunite the calf with whale pods by luring it out to sea, it returned to Pittwater. Opinion was divided on how best to handle the situation, with some advocating feeding artificial milk formula to the calf, and others advocating euthanasia.

Colin was euthanised on 22 August 2008 due to his deteriorating condition. The calf's plight gained media attention as far afield as the United States, United Kingdom, Italy, Netherlands, Russia, Canada and New Zealand.

A subsequent autopsy found that Colin was terminally ill with an emaciated pancreas, ulcers of the stomach and oesophagus, intestinal erosion and infected shark bites. The calf was estimated to be only 7 to 10 days old and must have been separated from its mother shortly after birth.

The Thames beaching

On 12 September 2009, a humpback was seen in the London Thames for the first time ever.[32217] The 9.5m young male was found beached and dead near Dartford bridge two days later on 14 September. Initial examination of the body suggested death had been by starvation, without any explanation of why this had occurred. Experts suggested that such events as these indicated the expansion of the areas colonised by humpbacks. [32218]

"George & Gracie"

George and Gracie were a pair of fictional humpbacks which featured prominently in Star Trek IV: The Voyage Home. In the film, Earth is threatened by large object that transmits a signal disabling the global power system and causing extreme weather patterns to develop. Spock determines the alien signal matches the song of humpback whales, extinct on Earth since the mid-21st century (at least 200 years). The crew devises a plan to go back in time, before the extinction, and return with a whale. Arriving in the late 20th century, Kirk and Spock are able to quickly discover a pair of humpback whales, "George" and "Gracie," at the Cetacean Institute, an aquarium devoted exclusively to whales, and are told by the Institute's whale expert, Dr. Gillian Taylor, that the whales are shortly going to be released into the wild, making the pair ideal for their needs. Despite some upsets and the threat of whalers, the crew is able to return to the future, splashing down into San Francisco Bay, where Kirk releases the whales from the cargo hold. The whales respond to the alien signal, causing the object to restore Earth to its normal condition and to return to the depths of outer space.

Industrial Light & Magic created the visual effects. Most shots of the humpback whales were scale models shot at their studio or life-size animatronics shot at Paramount However, some of the shots, including a scene of a whale breaching are stock footage of actual animals.

Media

Footnotes

References

Books

Journal articles

External links

General

• US National Marine Fisheries Service Humpback Whale web page
• ARKive - images and movies of the humpback whale (Megaptera novaeangliae).
• Photos and information about humpback whales and other cetaceans in Mayumba National Park
• Humpbacks of Hervey Bay, Queensland, Australia
• The Dolphin Institute Whale Resource Guide and scientific publications
• Humpback Whale Gallery (Silverbanks)
• Humpback whale videos
• Book about the two humpback whales lost in the Sacramento River in May 2007 -
• The Humpback Whales of Hervey Bay
• Epic humpback whale battle filmed

Humpback whale songs

• A detailed analysis of the form and function of the humpback whale song, from the University at Buffalo
• The Whalesong Project
• Article from PHYSORG.com on the complex syntax of whalesong phrases

Conservation

• Estimating the humpback population in the Pacific, from the National Oceanic and Atmospheric Administration
• Estimating the humpback population in the Atlantic, from Dalhousie University
• Recovery plan in Australia: 2005–2010
• Humpback Whales in the Sacramento River by the NOAA
• The Oceania Project, Humpback Whale Research, Hervey Bay