Search results
Results from the WOW.Com Content Network
The family Balaenidae, the right whales, contains two genera and four species. All right whales have no ventral grooves; a distinctive head shape with a strongly arched, narrow rostrum, bowed lower jaw; lower lips that enfold the sides and front of the rostrum; and long, narrow, elastic baleen plates (up to nine times longer than wide) with fine baleen fringes.
The narwhal is a stocky cetacean with a relatively blunt snout, a large melon, and a shallow ridge in place of a dorsal fin. Males of this species have a large (1.5–3.0 m (4 ft 11 in – 9 ft 10 in)) long tusk, which is a protruding left canine thought to function as a weapon, a tool for feeding, in attracting mates or sensing water salinity.
The traditional hypothesis of cetacean evolution, first proposed by Van Valen in 1966, [9] was that whales were related to the mesonychians, an extinct order of carnivorous ungulates (hoofed animals) that resembled wolves with hooves and were a sister group of the artiodactyls (even-toed ungulates). This hypothesis was proposed due to ...
Whales do not form a clade or order; the infraorder Cetacea includes dolphins and porpoises, which are not considered whales in the informal sense. [citation needed] The phylogenetic tree shows the relationships of whales and other mammals, with whale groups [citation needed] marked in green.
Cetaceans are famous for their high intelligence, complex social behaviour, and the enormous size of some of the group's members. For example, the blue whale reaches a maximum confirmed length of 29.9 meters (98 feet) and a weight of 173 tonnes (190 short tons), making it the largest animal ever known to have existed. [5] [6] [7]
Perrin's beaked whale (Mesoplodon perrini) is part of the toothed whale suborder and is one of over 90 known cetaceans in existence today. [3] Beaked whales are part of the family Ziphiidae , which are the second most diverse group out of all marine mammals with over 20 species currently recognized. [ 4 ]
Ranging from 9 to 98 feet in length, whales are the largest creatures on Earth. ... Whales are a part of the cetacean family, which is divided into two groups: baleen whales ...
Cetaceans are long-lived animals (particularly whales), with a theoretically low mortality rate once they reach adulthood and virtually no predation, even if they remain exposed to diseases and parasites (which are thought to be involved in 25% of cetacean deaths in the Mediterranean, particularly when their proliferation becomes pathological ...