The study of fossils indicates that the ancestors of today's whales gradually returned from land to live in the sea. The young are cared for until they are old enough to look after themselves. Whales have nostrils, called blowholes, which open on the top of the head so that the whale can breathe air out and rapidly suck fresh air in without stopping swimming. The whale's body is streamlined so it can swim more easily. The tail has developed into a powerful horizontal fin called a fluke, and the forelimbs have become flippers which the whale uses to steer and change its position in the water.
Some whale species seem to be able to communicate over long distances.
There are two groups of whales, the baleen whales and the toothed whales. Baleen whales include the blue, sei, fin, Bryde's, humpback, bowhead, minke, grey, right and pygmy right whales. All but the bowhead and grey whales can be found in South African waters. These small animals are the whales' food. These whales eat fish and squid.