Whale (origin
Old English hwael)
[2] is the common name for various
marine mammals of the order
Cetacea.
[2] The term
whale is sometimes used to refer to all cetaceans, but more often it excludes
dolphins and
porpoises, which are also
cetaceans[3] but belong to the suborder
Odontoceti (
toothed whales). This suborder also includes the
sperm whale,
killer whale,
pilot whale, and
beluga whale. The suborder
Mysticeti (
baleen whales), are
filter feeders that feed on small organisms caught by straining seawater through a comblike structure found in the mouth called
baleen. This suborder includes the
blue whale, the
humpback whale the
bowhead whale and the
minke whales. All Cetacea have forelimbs modified as fins, a tail with horizontal flukes, and nasal openings on top of the head.
Whales range in size from the blue whale, the
largest animal known to have ever existed
[4] at 35 m (115 ft) and 150 tonnes (150 LT; 170 ST), to various pygmy species, such as the
pygmy sperm whale at 3.5 m (11 ft).
Whales collectively inhabit all the world's oceans and number in the millions, with population growth rate estimates for various assessed species ranging from 3% to 13%.
[5] For centuries, whales have been
hunted for meat and as a source of raw materials. By the middle of the 20th century, however, industrial whaling had left many species seriously
endangered, leading to the end of whaling in all but a few countries.