Baleen Whales (Mysticetes)

Abstract

This chapter explores the baleen or whalebone whales (Mysticeti), one of the two recent (non-fossil) cetacean suborders. Modern baleen whales differ from the other suborder (toothed whales, Odontoceti), particularly in their lack of functional teeth. Instead they feed, on relatively very small marine organisms, by means of a highly specialized filter-feeding apparatus made up of baleen plates (“whalebone”) attached to the gum of the upper jaw. Other differences from toothed whales include the baleen whales' paired blowhole, symmetrical skull, and absence of ribs articulating with the sternum. Baleen whales are generally huge. The blue whale, the largest known animal, grows to more than 30 m long and weighs more than 170 tons. Like all other cetaceans, baleen whales are totally aquatic, and like most of the toothed whales, they are all marine. Many undertake very long migrations, and some are fast swimming. A few species come close to the coast at some part of their life cycle and may be seen from shore; however, much of their life is spent far from land in the deep oceans. Baleen whale females grow slightly larger than the males. Animals of the same species tend to be larger in the Southern than in the Northern Hemisphere.