Author: Monica Lozano Subiranas
The humback whale frequents our coastline in the winter months from June to November and can put on a spectacular show. Here are some interesting facts on this whale.
Length: Male - 17 metres / Female - 18 metres.
Weight: up to 40 tons.
Calf length: 5 metres.
Calf weight: 900 Kg.
Diet: Krill, schooling fish.
Features: 5m long flippers, callosities, tubercles, throat grooves.
Behaviour: Breaching, lobtailing (tailslap), inverted lobtailing (belly up), flipper slapping, rolling.
Lifespan 50 years. Gestation lasts for about 11 months. Newborns are 4 - 5m long and grow quickly from the highly nutritious milk of their mothers. Weaning occurs between 6 - 10 months after birth. Mothers are protective and affectionate towards their calves, swimming close and frequently touching them with their flippers. Males do not provide parental support for calves. Breeding usually occurs once every two years, but sometimes occurs twice in a three year span.
The scientific name is Megaptera novaeangliae which means "big winged New Englander" because of its long flippers and was first described in New England. They are called humpback but don't have a real hump, but by the way they arc their bodies when taking a deep dive looks like a bump.
Individuals found in the southern hemisphere are generally more lightly coloured on the flanks. The bumps on the head are called tubercles, and each one contains a single hair follicle, which may be used in a sensory capacity, much like a cat's whiskers. The flukes (tail) are unique to each animal, much like a human fingerprint, allowing experts to name thousands of individuals around the world, The wavy edged flukes are raised during dives, enabling researchers to keep track of individual whales from year to year.
During the summer months, humpbacks spend the majority of their time feeding and building up fat stores (blubber) that they will live off during the winter. They filter feed mainly on tiny crustaceans (mostly krill), plankton and small fish and can consume up to 1360 kg of food per day. Several hunting methods involve using air bubbles to herd, corral or disorientate the fish. One highly complex variant called "bubble netting" is unique to humpbacks and is often performed in groups with defined roles for distracting, scaring and herding.
In their wintering grounds, humpback whales congregate and engage in mating activities. They are normally polygymous with males exhibiting competitive behaviours like chasing, vocal, bubble displays, horizontal tail thrashing and rear body thrashing. Males also sing complex songs that can last up to 20 minutes and can be heard great distances underwater. All males in a population sing the same song, which evolves over time.
Humpback whales travel great distances during their seasonal migration, the furthest migration of any mammal.