This site is indebted to the writings of Lyall Watson (amongst others), for his amazing and well-researched book Whales of the World, illustrated by Tom Ritchie.

HUMPBACK WHALE – Megoptera novaeangliae

Description Large; length averages 14.6 m (48 ft) for males, with a maximum of 17.5 m (58 ft), and 15.2 m (50 ft) for females, with a maximum of 19 m (62 ft); calves are about 4.5 m (15 ft) at birth. Weight averages 30,000-40,000 kg (34-45 tons) for both sexes, with a maximum of 48,000 kg (53 tons); calves are about 1,300 kg (1.5 tons) at birth.
Although Humpback Whales are still classified in the family Balaenopteridae, they are unlike the corquals. The body is robust, narrowing rapidly in front of the huge tail flukes.

The head is broad and rounded, in some ways like that of the Blue Whale (B. musculus 6), but the median ridge is indistinct and has been replaced by a string of fleshy tubercles or knobs. Two further lines of these are arranged along the margins of the jaws; and there is a larger, more rounded, projection near the tip of the lower jaw. Each bump has a long coarse hair growing directly out of its centre.
The fin is small and varies in shape from triangular to sharklike. It is set two-thirds of the way back, in roughly ,the same position as that of the Fin Whale, but is mounted on a distinct fleshy step or platform unlike that of any other baleen whale.

The most characteristic features are the enormous flippers which are almost a third of total body length (about 5 m or 16 ft long in an adult) and heavily scalloped on the leading edge. The trailing edge of the tail flukes is similarly serrated. The colour is generally blackish with a white area covering the throat grooves. The flippers are almost pure white below and mottled black and white above. The underside of the flukes is marked with a variable pattern of white, making each whale recognizable at the surface as it throws its tail into the air before sounding.

Field Identification Humpback Whales at a distance can look a little like some rorquals, but the Humpback's habit of raising the tail flukes before sounding sets them apart. Great Sperm Whales (fhyseter macrocephalus 36) also throw their tails in the air, but have no white markings on them at all.
The Humpback's blow is distinctive, seldom more than 3 m (10 ft) high, and is a broad, bushy balloon of spray. The usual breathing sequence involves 2-3 minutes at the surface, blowing once every 20-30 seconds, followed by a deep hump backed dive for 3-28 minutes. The fin is seldom seen until the high rolling dive that brings the hump into view before sounding.

In warmer water, the number of breaths taken between dives is reduced from an average of 6 to 2-3.
Humpbacks often leap clear of the water, usually in an arching backward flip which brings the pale pleats of the throat into view. On occasion these whales can be found lying motionless at the surface with one long flipper hoisted like a sail. When disturbed, or sometimes for no apparent reason, they slap the water hard producing a report like a rifle shot; or lobtail, bringing the tail down sharply in an even louder smack against the surface. All these sounds may have a signal function, keeping a scattered group of whales in touch, or warning each other of intruders.

In our experience Humpbacks show very little fear of boats, large or small. We have been able to motor close to these whales in our inflatable boats and have even had an adult come to scratch its back on the hull of our stationary ship. This fearless attitude is shown when the whales are busy on their polar feeding grounds or clowning in the warmer waters of the tropics. Everywhere the response and the experience are the same: groups of grotesque and beautiful monsters, filled with what seems like joie de vivre, breaching and falling, splashing and tailing, rolling, scooping, finning or bursting out together in great backward somersaults.

Stranding Possibly as a result of their familiarity with shallow waters, Humpbacks rarely strand. The occasional dead one presents few problems of identification. Out of water, these lithe acrobats become stocky and inflated as the sleek lines are destroyed by gravity and the relaxation of the great throat muscles. flippers, tuberosities on the head and the lump on the lower jaw are all distinctive. So too are the throat grooves: Humpbacks have fewer grooves, 4-24 (average 22), set more widely apart, than any rorqual. The baleen is also characteristic. There are 270-400 plates (usually 330), each up to 65 cm (25 inches) long, dark grey or olive brown with light grey bristles.

The rough, knobbly skin provides great scope for ectoparasites. Humpbacks in cold waters are infested with up to 450 kg (half a ton) of the sessile barnacles CoYOnula dradema and C. reginae. One favours the lips and tail and is usually so deeply embedded in the skin that only the crown shows, while the other perches on the tubercles. A long-necked goose bar¬nacle which never parasitizes the whale directly often sits on top of the barnacles. As the whales move into warmer waters, the barnacles tend to drop off, leaving the field clear for the whale lice, notably Cyamus hoopis found only on the Humpback.

The skull differs noticeably from that of the rorquals in having a more curved lower jaw. There are 52-53 vertebrae and, in some individuals, remnants of hind limbs. A Humpback landed on Vancouver Island in Canada had internal legs 1.2 m (4 ft) long.
Natural History Humpback baleen is coarse and stiff, excluding the possibility of feeding on smaller forms of plankton. But in the southern hemisphere the whales live mostly on swarming crustaceans, mainly species of Euphausia, Munida and Thysanoessa. In the northern hemisphere the various forms of krill are largely replaced by shoaling fish such as the capelin, anchovy and cod . A few groups of Humpbacks even follow trawlers to take advantage of their spill.
Normally Humpbacks feed by lunging forward at the surface or by rushing on their prey from below, surfacing through the school with their mouths open. The Alaskan population have however developed a technical refinement involving the creation of a bubble net to trap and concentrate the prey long enough for them to grab it. To do this, the whales start IS m (50 ft) below the surface, weaving a net of bubbles by forcing air out through their blowholes as they swim upwards in a tight spiral, finally surfacing open mouthed right amongst the food. It may be possible for a whale to make a net with the most efficient grade of mesh by selecting the bubble size it uses, or for rwo whales to collaborate on a net 30 m (100 ft) or more in diameter.
The normal social unit seems to be a small family group of 3 or 4, often loosely tied by sound signals to other more distant groups of similar size. In animals like these, whose calls may travel for hundreds of kilometres, the normal human concept of a herd (that is a gathering of individuals all visible to us at the same time) breaks down altogether. for all we know, every Humpback in the entire north-west Atlantic Ocean
could be part of a single socia] system.
Humpbacks mature in less than 10 years, when males are II m (36 ft) and females 12 m (40 ft) long. Mating takes place on communal breeding grounds in warmer waters, usually in shallow bays Within the 100 m (330 ft) contour. Courtship is playful and splashy, often social, involving an energetic group that races along the surface at breakneck speed, churning the water up into turbulent knots of breaching, slapping whales. Sometimes the confusion ends in a single pair rising, with their flippers interlaced, belly-to-belly above
the surface, clasping each other and holding that position for 30 seconds or more until they shudder and subside again.
Gestation lasts for 11-12 months and calves nurse until they are almost a year old and 8 m (26 ft) long. During this time it is common to see a mother and her calf together with a third whale, a mysterious escort, who is sometimes an adult male. There are records of both animals acting protectively toward the infant, in one case of a mother taking her young calf under a flipper to protect it ..
New mating frequently takes place soon after birth, so
Humpbacks can and may breed every year.
Intensive observation in the clear water of winter breeding grounds off the Hawaiian Islands is beginning to provide detailed information which makes the Humpback the best known of all baleen whales; but we are still far from under¬standing even the rudiments of their complex social
behaviour.
Humpbacks produce the longest and most varied songs in the animal world. These are intricate fabrics of sound, ranging from pure high-frequency whistles to low and resonant rumbles which can even be heard above the surface.
At first, each song seems to consist of random grunts, groans, moos, rasps and twitters, but analysis shows that there are long, organized sequences. Each sequence normally lasts 10-15 minutes and may be repeated over and over again, without pause, for hours. It is made up of short sound units combined into phrases which form unbroken parterns or themes. These recognizable themes are subject to individual interpretation, but always arranged into cycles characteristic of each population, so that all Humpbacks in one area sing only the local song. Evidence shows that these songs evolve with time. Each year the song is a lirtle different, but every change is picked up and incorporated in the current pattern and in the appropriate local dialect by all singers in a given
population.
There is now a vast library of recorded songs, mainly from
Bermuda and Hawaii, but we still know little about just who sings, or why. Singing is more common in, and perhaps even largely confined to, the breeding season; it usually seems to be a solitary whale, possibly a male, who sings. The song may function as sexual display, advertising the presence of a breeding male and keeping a family group together, but the com¬plexity of the cycle suggests that there is more to it than that. In addition to the ritual announcement, there may be new information or the preservation of old in something like a simple folklore. Before any conclusions can be reached, it will be necessary to know exactly which individual is singing and to establish its age, sex and relationship to all those within hearing range; and then to document their direct response to the singer and the song. A start has been made by Roger and Katy Payne and their co-workers.

Above illustration and excerpt from:
Lyall Watson, Sea guide to Whales of the World, illustrated by Tom Ritchie, Hutchinson 1981.