Family: Balaenopteridae, Rorquals view all from this family

Description To 98' (29.9 m). Fusiform, tapering posteriorly; light bluish-gray above mottled with gray or grayish-white, belly sometimes yellowish, baleen plates black. Rostrum broad, flat, nearly U-shaped, with single median dorsal ridge; paired blowholes on top of head. Dorsal fin extremely small, nearly triangular to falcate, far back on tail stock. Ventral grooves extend to or slightly past navel. Blow high, oval.

Endangered Status The Blue Whale is on the U.S. Endangered Species List. It is classified as endangered in the states its range reaches, California and Massachusetts. Whalers in the 19th and 20th centuries hunted this giant nearly to extinction, killing 29,000 in 1931, probably the peak year. Since coming under the protection of the International Whaling Commission in 1965, the Blue Whale has shown encouraging signs of recovery. Its numbers do not approach what they were before its exploitation, but they have been on the increase in the North Pacific and North Atlantic Oceans. Whereas there were once probably 200,000 Blue Whales in Earth's oceans, today there may be about 5,000.

Similar Species Sei White (B. borealis) has dorsal fin placed two-thirds of body length back from head. Fin Whale (B. physalus) has more V-shaped rostrum.

Habitat Usually open seas, but sometimes in shallow inshore waters.

Range In Atlantic from Arctic Circle to Panama, including NW. Gulf of Mexico. In Pacific from S. Chukchi Sea to Panama.

Discussion The yellowish coloring on the belly of this species is due to diatoms accumulated in colder water, inspiring the alternate name Sulphur Bottom Whale. It is a relatively shallow feeder, and its diet consists mainly of krill. The Blue Whale is probably the largest animal known, even larger than the dinosaurs. It has been estimated to reach a weight of about 196 tons (178,000 kg).