Whale
Whale (origin Old English hwæl) is the common
name for various marine mammals
of the order Cetacea. The term whale sometimes refers to all
cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti (toothed whales). This suborder
also includes the sperm whale,
killer whale, pilot whale, and beluga whale. The other Cetacean
suborder Mysticeti (baleen whales)
are filter feeders that eat 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 whale. All Cetacea have
forelimbs modified as fins, a tail with horizontal flukes, and nasal openings
(blowholes) on top of the head.
Whales range in size from the blue
whale, the largest animal
known ever to have existed at 30 m
(98 ft) and 180 tonnes (180 long tons; 200 short tons), 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 annual population growth rate
estimates for various species ranging from 3% to 13%. 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.
