The general pattern of life for the baleen whales is to breed in the temperate and warm equatorial waters in the winter months, and to feed in more polar waters during the summer.
Most species carry out long migrations each year between the breeding and feeding areas.
Because the seasons are opposite in the Northern and Southern Hemispheres, whales in the two halves of the world do not mix. Feeding The baleen whales have several hundred elongated triangular baleen plates growing down on either side from the roof of their mouths. These plates are made of a horny material and not of bone, even though they are popularly called whalebone. The whale takes in a large mouthful of water containing the shrimps or other small crustaceans or fish on which it feeds. When the mouth is closed, the throat region tightened and the large tongue pushed up, the water is forced out between the baleen plates and the food is left trapped and can be swallowed.