Text
E-book Dolphins, Porpoises and Whales of the World : The IUCN Red Data Book
The mammalian order catacea includes three suborders: the archaeoceti ancient whales, extinct forms known only from fossils. including at least ten living species of baleen or whalebone whale; and the odontoceti or toothed whales, including about 70 living species of dolphins, porpoises, and whales with teeth but no baleen. So far, humans have not driven any cetacean species to extinction, although some are now severely threatened. The cetaceans are mammals which spend all their live in water, and have evolved many adaptations to this way of life. The body is streamlined with no hind limbs, reduced forelimbs and a powerful horizontal tail for propulsion. The nostrils have become blow holes at the top of the head to facilitate respiration while travelling through the water; baleen whales have two, toothed whales one.
Tidak tersedia versi lain