What name is given to lung-breathing aquatic mammals such as whales, porpoises and dolphins?
Cetacea Cetacea Cetacea () is a widely distributed and diverse clade of aquatic mammals that today consists of whales, dolphins, and porpoises. Cetaceans are carnivorous and finned. Most species live in the sea, some in rivers. The name is derived from the Latin "cetus" "whale", itself from the Greek κῆτος "kētos" "huge fish". There are around 89 extant species, which are divided into two groups or parvorders, the Odontoceti or toothed whales, a group of more than 70 species that includes the dolphins, porpoises, belugas, narwhals, sperm and beaked whales, and the Mysticeti or baleen whales, of which there are now
Physiology of underwater diving slight decrease in threshold for taste and smell after extended periods under pressure. Aquatic mammals such as seals and whales dive after full exhalation, which would reduce the amount of nitrogen available to saturate the tissues by 80 to 90%. Aquatic mammals are also less sensitive to low alveolar oxygen concentrations and high carbon dioxide concentrations than purely terrestrial mammals. Seals, whales and porpoises have slower respiratory rates and larger tidal volume to total lung capacity ratio than land animals which gives them a large exchange of gas during each breath and compensates for low respiratory rate. This allows greater