• Overview
• Common Names
• Description
• Biology
• Taxonomy
• Similar Species
• Bibliography
• More Info
• Notes

Overview

The Humpback Whale is a widely distributed species, occurring seasonally in all oceans from the Arctic to the Antarctic , with distinct populations located in virtually every sea . All populations of Humpback Whale undertake vast migrations between breeding and feeding grounds , the most famous - and longest - of which is probably made by the Hawaii Humpbacks, who travel to the Bering Strait and Alaska's Glacier Bay every year to feed .

Humpback whales are mysticetes, (baleen whales ), in the family Balaenopteridae which includes fin , blue, sei, Bryde’s, and minke whales, the rorquals . All rorquals have a small dorsal fin and longitudinal throat grooves or pleats from their chin to their navel that expand when they feed. The common name , humpback, comes from this whale’s appearance when it arches its back out of the water in preparation for a long dive. These whales are noted for their haunting songs, acrobatic behaviors, and the cooperative feeding methods they use. Easily identified because of the distinctive variability of the black and white patterns on the undersides of their flukes , photo-identification of humpbacks whales started in 1970. Today humpback whales and orcas are the most studied of all the cetaceans .

Vulnerable

Common Names

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Description

Family Balaenopteridae

This family contains the larges animals ever to live; all balaenopteroids have adult body lengths of over 7 m , but some are much larger. The rorquals are streamlined animals (the humpback whale somewhat less than the others), with a series of long pleats extending from the snout tip to as far back as the navel on the ventral surface. Balaenopterids are fast and active lunge feeders ; their morphology allows them to open their jaws very widely and distend their throats to take in huge mouthfuls of water during feeding. The baleen plates are of moderate length and fringe fineness. Density and fringe diameter vary among species, and along with plate number and width to length ratio, are diagnostic characters. Rorquals have dorsal fins (varying in size and shape ) set beyond the midpoint of the back. The upper jaw has a relatively flat profile , a feature reflecting the structure of the skull. Within a given feature, differences among balaenopterids are often subtle variations on a theme, rather than class distinctions. Therefore, information on many features may be needed to distringuiish among them and reliance on a single character for identification is discouraged.

Physical Description

Habitat

During summer months these seasonal migrants are found near oceanic islands , coastal areas, and over the continental shelf or at its edges feeding in relatively shallow temperate and cold waters . They migrate to tropical waters during the winter where they breed and calve . They may travel across deep ocean waters during their migrations.

Typically found in water with a depth of 0 to -6,280 meters (0 to -20,604 feet).Mean = -360.100 meters (-1,181.430 feet), Standard Deviation = 955.950 based on 16,797 observations. Ocean depth information for each observation from British Oceanographic Data Centre.

Biome: Marine

Ecology: List of Habitats : 9.1 Marine Neritic - Pelagic 10.1 Marine Oceanic - Epipelagic (0-200m)

Biology

Diet

Northern Hemisphere humpbacks prefer a diet of small fishes (herring , capelin, mackerel , and sandlance), and krill, small shrimp-like crustaceans while the diet of Southern Hemisphere whales is primarily Antarctic krill, >i>Euphausia superba,. They lack teeth to grip and tear large prey into small easily swallowed pieces , so items on their menu must be small. It is estimated that adult humpbacks eat 1360 kg (2998 lb ) of food each day.

Humpbacks are filter feeders . Their baleen plates have bristly inner edges that intertwine to form a strainer or filter. Although their large mouth opens to an angle greater than 90o, like most baleen whales , their throat is so small that they cannot swallow large prey. Normally feeding in the top 100 m (330 ft ) of the water column , they lunge at their meal , plowing through concentrated swarms or schools of prey with huge mouth open and throat grooves expanding to form a large sack to take in as much as 10,000 liters (2642 gal ) of food-laden water. The water is expelled through the baleen and the whale uses its large rasping tongue to maneuver the food retained on the inner surface of the baleen to its throat to be swallowed whole.

In addition to lunging, humpbacks have several other unique feeding behaviors some of which involve blowing bubbles by one whale or by several hunting cooperatively. .

Bubble netting : One or more whales dive beneath a school of fish and swim upward in ever smaller concentric circles as they release streams of air from their blowholes to create bubbles. The bubbles rise in a net around the fish seeming to form a barrier that the fish will not pass . The whale(s) then swim up through the middle of the net, mouth wide open to feed Bubble feeding: Pod exhales columns of bubbles to herd prey into a ball , then lunge feed in formation Bubble cloud: Burst of bubbles up to 20 m (66 ft) across traps prey between the surface and the rising cloud for lunge feeding.

Reproduction

Humpback whales reach sexual maturity between six and ten years of age. Their breeding areas are fairly well known, unlike those of most other baleen whales . Males court females with song. (See Adaptation for information about vocalization of humpbacks.) They also engage in vigorous, even violent competition , for mates. On the breeding grounds there may be two to more than 20 males around a single female with the group composition changing periodically. When a male, called a joiner, approaches a singer and tries to get close to the female being courted, the males lunge at each other, lash with flukes , flippers, and tails, and blow clouds of bubbles. Head slapping, butting, and serious push and shove behavior is exhibited.

The gestation period is 11-12 months. When ready to give birth, the female seeks a relatively shallow inshore area where she may be safe from sharks , boats , and aggressive males. The calf is 4-4.6 m (13-15 ft ) long at birth and weighs about 680 kg (1500 lb ). The calf nurses for 8-11 months, supplementing its milk diet with seafood when it is six months old. It gains weight rapidly consuming milk that is 45-60% butterfat.

Often a cow-calf pair is accompanied by another adult known as an escort. Escorts can be of either sex but are most often males seeking to breed . The escort remains with the pair for only a few hours.

Behavior

Migration Depending on starting and ending points , humpbacks may have one of the longest migrations of any mammal, traveling as many as 16.000 km (10,000 mi ).They usually travel in small groups of three to four whales . Different populations follow definite paths, usually the same route each year, as they migrate from summer feeding grounds in cold and temperate waters to warmer water winter breeding and calving areas. Immature whales do not always make the entire migration, stopping at points along the way. The populations in the various parts of the world ocean are all genetically separate subspecies and, while they may co-mingle in breeding grounds , they rarely if ever interbreed. The group inhabiting the Arabian Sea does not seem to migrate.

In the western North Pacific the whales that breed and calve around Japanese islands probably travel to the Bering Sea and the Aleutian Islands to feed over summer/fall. The coastal Central America and Mexican whales feed off of the coast of California to southern British Columbia. Hawaii’s breeding/calving population migrates to northern British Columbia, southeast Alaska, and Prince William Sound west to Kodiak.

The North Atlantic populations feed between the Gulf of Maine, Iceland, and Greenland and off the coast of Norway. The western Atlantic whales migrate to the Caribbean to winter although recently juveniles have been sighted from Delaware to North Carolina. The eastern Atlantic humpbacks breed and calve off the coast of Africa and the Cape Verde Islands.

During the austral summer the Southern Hemisphere’s six main humpback populations intermingle while feeding in the Southern Ocean around Antarctica. However, they usually return to their home areas on each side of Australia, Africa, and South America to breed and calve.

Blow : The blow of humpback whales is low, rounded , and more bushy than other rorquals . In preparation for a deep dive they take 4-8 breaths at 1-2 minute intervals and then dive to a depth of 150-210 m (492-689 ft ). In the breeding grounds (where they do not usually feed), they blow 3-6 times between dives. The average dive lasts up to 15 minutes. When feeding, they usually swim 1.9-5.6 km/hr (0.2 -3.5 mph). Otherwise their swimming speed is 4.8-14 km/hr (3-9 mph).

Known as the singing whales, male humpbacks are the singers, not females. The singing male positions himself vertically in the water head down and sings a song that is loud, repetitive, and the most complex sung by any animal in the world. It is made up of grunts , chirps, violin-like sounds, rumbles, whoos, and eees. Phrases are organized into themes and the themes into songs that may be sung over and over being repeated for hours. The low frequency noises can travel 30-35 km (18.6-21.8 mi).

Although the songs of individuals may vary somewhat, all whales in a group sing essentially the same song which differs from that of other populations, i.e. , there is a regional dialect. A portion of the song is changed each breeding season with some parts deleted and new ones added. All males in the group make the changes.

In the breeding grounds the singing is to attract a mate and singing decreases markedly when the whales start their migration to feeding grounds. In addition to mate attraction as a reason for singing, other reasons may be to show dominance or aggression , a way to stay in touch on the migration or give information about the journey, or to let others know the location of prey , important in cooperative feeding.

The Acrobatic Whales: Humpbacks have a repertoire of spectacular acrobatic behaviors. Many of their displays seem to be involved in courtship and breeding, while reasons for others are still not well explained.

breaching : lifting as much as two thirds of the body out of the water and landing on the surface belly down or on the side with a thunderous splash. The breach of a humpback is the most dramatic of all whales. Is this to get rid of parasites, communicate with other whales, a courtship display, a temper tantrum, or just for fun? spyhopping : lifting the head out of the water vertically, usually clearing the eyes above the water surface to scan for about 30 seconds, then slowly sinking down. The whale does not swim when spyhopping but relies on exception buoyancy control and position with its flippers. Why look around? Perhaps, to see who is in the area, where obstacles are, to navigate, or just out of curiosity. head lunging : thrusts head toward another whale in a threatening posture, often butting it. An aggressive mood to chase away competitors for attentions of females?

head slap: head forcefully hurled onto surface of water. Another aggressive move?

flipper slap: slapping surface of water forcefully with a flipper. Communication?

flipper waving: while lying on its side, lifts entire flipper above the water for as long as an hour. Attract a mate? Occurs in or near breeding areas.

tail lobbing: raising fluke out of the water and then slapping it on the surface. Aggressive temper tantrum or communication?

Humpback Whales often congregate in large, loose groups of tens of animals for breeding and feeding, but within these groups they move individually or in the companionship of between 1-3 others. On breeding grounds the well-known 'gentleness' of these animals is abandoned, with males becoming very aggressive as they attempt to claim females for their own. It is with these breeding grounds that the Humpbacks are most commonly associated with their 'singing', which is well-known for being included on the Voyager space mission, along with the golden plaque . The songs can vary from 35 minutes to days in length, with pauses only for breath. It is the males that sing in this fashion. The most acrobatic of large whales, Humpbacks are also well-known for their breaches - one was recorded breaching 200 times in a row - lob-tailing and flipper-slapping . Some Humpbacks in Alaska have been seen rolling over icebergs in play.

Taxonomy