Humpback whale

Megaptera novaeangliae

Humpback whale Humpback whale
The Humpback whale is one of the most commonly seen by Whale Watchers, in both hemispheres of the planet.
The following distinctive features makes it generally very easy to positevely identify a Humpback whale.
  • Very long, knobby flippers (pectoral fins), which can be as long as 1/3 the total body length and can present extensive white patches, especially in individuals of the Northern Hemisphere populations.
  • Numerous knobs around the snout.
  • Blue to almost black back.
  • Individual in the Southern Hemisphere are characterised by a white belly.
The Humpback whale belongs to the group of whales generally called Rorquals (from a Norwegian word meaning "furrow whales"), more precisely defined as the species belonging to the family Balaenopteridae, which have pleats (e.g. grooves) on their throats.
The accordion-like pleats are highly extensible, and let the whale engulf a very large amount of water, which is then filtered by the comb-like baleen plates. While water is expelled through the baleen, food is retained in the whale's mouth and finally swallowed. The Humpback whale is by far the most acrobatic of large cetaceans.
They frequently breach, lob-tail, flipper-slap and spyhop. All these behaviours really make the joy of Whale Watchers, along with the Humpback whale's tendency to be often inquisitive and approach non-harassing boats. The name "Humpback" is self-explanatory: this whale is characterised by a strongly arched back, mostly noticeable when the animal is just about to leave the surface.
The dorsal fin can be low and stubby, or quite high and with a more defined "fin-like" shape, depending on the individual. The Humpback whale is widespread in the Earth's oceans, but its seasonal distribution is precisely defined. Indeed, the Humpbacks prefer to spend their winters in warm, calm waters, where they mate, breed and suckle their calves.
They do not feed during the winter, but only in the summer when they reach their feeding grounds by following distinct migration patterns to the high latitudes of the Arctic (in the Northern Hemisphere) and Antarctica (in the Southern Hemisphere). It is in fact in the cold and rich waters of the extreme North and South of the planet that Humpback whales regain weight by eating amazingly large amounts of krill (a small crustacean) and schooling fish. Humpback whales are famous for a feeding technique known as bubble-netting.
In bubble-netting a group of highly coordinated whales encircle a school of fish, while some of the individuals blow air bubbles underwater through their blowholes. The net of bubbles acts as a wall for the fish, which is then pushed towards the surface, where most whales take advantage of the situation by swimming into the dense fish school with their mouths open. Female Humpbacks calve every 2 or 3 years. Births occur in winter, far away from the high latitude harsh conditions which would be too strenuous for the babies. Mum and calf pairs are often accompanied by "Escort" males, who patiently (not really, actually!) wait for the female to become again receptive. This is the time of the year when the wonderful Humpback whale's songs can be heard. Only the males sing, and they can perform for hours, sometimes entire days, while staying head down underwater, motionless.
Their songs are so powerful that can be heard from miles and miles. The Humpbacks seem to use rhymes to make it easier to remember their complex tunes, which are shared by all males in a certain area. Songs then change with time, and all whales start to sing the new tune. The Humpback whale is a slow swimmer, and partly because of that it was heavily hunted during whaling time.
While some populations seem to have recovered quite well, its conservation status is still defined as Vulnerable.
Indeed, some of the previous well known migration routes have completely disappeared, most notably the ones along the coasts of New Zealand, despite the fact whaling stopped in New Zealand more than 50 years ago.