Humpback Whale – Megaptera novaeangliae
The Humpback Whale belongs to the family of rorqual and is thus part of the infraorder of the whales. Megaptera novaeangliae was first described by Borowski in 1781.
Description, Anatomy & Characteristics
The Humpback Whale can best be distinguished from similar species by its particularly large flippers. These reach about a third of the body length. In addition, the body is very strong, thus less slender than with other rorqual.
While the back is black, the colouration of the belly depends on the population and varies from white to black. In addition, it has white spots distributed over its body, which are caused by barnacles. It is also possible that the body is covered with yellowish diatoms.
Megaptera novaeangliae grows up to 18m long, reaching a maximum weight of 30t.
Since it belongs to the baleen whales, the Humpback Whale has no teeth. Instead there are 270 to 400 baleen in its mouth, which are up to one meter long and coarser than other species.
Habitat, Distribution & Occurrence
The Humpback Whale lives worldwide, in all oceans. It prefers flat coast-waters on that occasion. However, it avoids most seas with narrow entrances. However, they may swim in bays and estuaries. They cross deep waters during their migrations, but still stay close to the coast.
While Megaptera novaeangliae visit the tropical latitudes towards winter, they spend the summer months in the polar zones. It is assumed that the individual populations do not cross the equator, so that southern and northern animals do not meet. An exception are the populations of the Indian Ocean, which cannot migrate north. They either stay in tropical latitudes all year round or migrate south into the Southern Ocean.
When diving in the Canary Islands it is very unlikely to be observed. However, it is occasionally seen on whale watching trips.
Biology & Feeding
Megaptera novaeangliae lives solitary or during hunting and mating in groups of 2 to 9 animals.
The Humpback Whale feeds mainly on krill, but also small schooling fish is on their menu. They only eat in their summer quarters and live off their fat reserves in the winter months.
With the hunt, it dives down up to 50m. At the surface, it lies horizontally in the water. If they ascend from bigger depth, they rise vertically. In order to push the loot into a dense swarm, the humpback-whale produces a curtain from air-bubbles.
Reproduction & Development
Megaptera novaeangliae mates during the winter months in tropical waters. Males show aggressive behaviour towards other males. With open mouth they threaten each other. In addition, they ram themselves and try to push other males away.
After mating, the partners usually stay together for a few hours and then look for other mating willing species. So the humpback whale is polygamous.
The gestation period of the females lasts almost exactly one year. The calves are therefore born again in tropical waters. A calf is about 4m long at birth. It remains with the mother for at least one year. The nursing period is six to ten months. Afterwards, the young moves on alone or joins another group.
With 12m and approximately 5 years, a Megaptera novaeangliae becomes sexually mature. With 15 years, it reached its final size. One assumes a maximum life expectancy around the 50 years.
The Humpback Whale & Orcas
The Humpback Whale is often an attack-target of the Orcas. Especially mothers with calves are attacked. This is why Megaptera novaeangliae often disturb Orcas during their hunt. Humpback Whales have been observed to disturb orcas that hunt seals, sea lions and other whale species. It has even been seen once how a seal was actively rescued from an ice floe.