North Atlantic right whale - Ecology & Habitat

A species with close attachments

This large whale mostly inhabits temperate waters, and compared to other similar-sized cetaceans is found more often in coastal waters, especially during the breeding season.

Social Structure
Whereas groups of North Atlantic right whales once numbered in the hundreds in feeding grounds, nowadays they usually travel alone or in groups of 2-3 (sometimes up to about 12).

Groups splinter off for feeding, probably because of the sheer quantity of food required for each animal. These aggregations are not fixed, and individuals have been observed to change groups. One notable exception is in the Bay of Fundy, where up to two-thirds of the remaining population aggregates in the summer to feed.

As with other mammals, right whale mothers and their calves display strong attachments, with the calf keeping in close contact with its mother by swimming up on her back or butting her with its head. Sometimes the mother may roll over to hold her calf with her flippers. Mating pairs are reported not to maintain long-term bonds.

Life Cycle
It is estimated that North Atlantic right whales live longer than 30 years.

Breeding
Females breed about once every three to five years. Gestation is about one year and the single calf is nursed for nine to 12 months. Pregnant females migrate to an area off the coast of Georgia and Florida to give birth between December and March and then migrate north to their feeding grounds in the Bay of Fundy. Scientists are confident there is at least one other nursery area but have yet to discover it. Where these whales mate is also a mystery.

In their feeding grounds in the Bay of Fundy in the summer, right whales are often seen in what scientists call "surface active groups" - groups may consist of just a few individuals or as many as 40 - which involve males and females making vigorous body contact. It is presumed that this is some type of courtship behaviour, though scientists believe it is too early for actual mating to occur, given what is known about the gestation period. The function of this intriguing social behaviour is not yet well understood.

Diet
North Atlantic right whales feeds mostly on copepods, and krill larvae. About 1,000 - 2,500 kg (2,200 - 5,500 lb) may be consumed every day. The North Atlantic whale feeds by swimming through a swarm of prey with its mouth open and the head slightly emerging on the surface. Having filtered the prey with its baleen plates, it drives out the water, dives, and swallows the food, a process known as "skimming".