The blue whale is a marine mammal and a baleen whale. Reaching a maximum confirmed length of 29.9 meters (98 ft) and weighing up to 199 tonnes, it is the largest animal known ever to have existed. The blue whale's long and slender body can be of various shades of greyish-blue dorsally and somewhat lighter underneath. Four subspecies are recognized: B. m. musculus in the North Atlantic and North Pacific, B. m. intermedia in the Southern Ocean, B. m. brevicauda in the Indian Ocean and South Pacific Ocean, B. m. indica in the Northern Indian Ocean. There is also a population in the waters off Chile that may constitute a fifth subspecies.
A mammal is a vertebrate animal of the class Mammalia. Mammals are characterized by the presence of milk-producing mammary glands for feeding their young, a neocortex region of the brain, fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors diverged in the Carboniferous Period over 300 million years ago. Around 6,400 extant species of mammals have been described and divided into 29 orders.
The Sirenia, commonly referred to as sea cows or sirenians, are an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters. The extant Sirenia comprise two distinct families: Dugongidae and Trichechidae with a total of four species. The Protosirenidae and Prorastomidae families are extinct. Sirenians are classified in the clade Paenungulata, alongside the elephants and the hyraxes, and evolved in the Eocene 50 million years ago (mya). The Dugongidae diverged from the Trichechidae in the late Eocene or early Oligocene.
Porpoises are a group of fully aquatic marine mammals, all of which are classified under the family Phocoenidae, parvorder Odontoceti. Although similar in appearance to dolphins, they are more closely related to narwhals and belugas than to the true dolphins. There are eight extant species of porpoise, all among the smallest of the toothed whales. Porpoises are distinguished from dolphins by their flattened, spade-shaped teeth distinct from the conical teeth of dolphins, and lack of a pronounced beak, although some dolphins also lack a pronounced beak. Porpoises, and other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates.
Vibrissae, more generally called whiskers, are a type of stiff, functional hair used by mammals to sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are coarser as tactile sensors. Although whiskers are specifically those found around the face, vibrissae are known to grow in clusters at various places around the body. Most mammals have them, including all non-human primates and especially nocturnal mammals.
River dolphins are a polyphyletic group of fully aquatic mammals that reside exclusively in freshwater or brackish water. They are an informal grouping of dolphins, which itself is a paraphyletic group within the infraorder Cetacea. Extant river dolphins are placed in two superfamilies, Platanistoidea and Inioidea. They comprise the families Platanistidae, the recently extinct Lipotidae, Iniidae and Pontoporiidae. There are five extant species of river dolphins. River dolphins, alongside other cetaceans, belong to the clade Artiodactyla, with even-toed ungulates, and their closest living relatives the hippopotamuses, from which they diverged about 40 million years ago. Specific types of Dolphins can be pink.
Iniidae is a family of river dolphins containing one living genus, Inia, and four extinct genera. The extant genus inhabits the river basins of South America, but the family formerly had a wider presence across the Atlantic Ocean.
The sperm whale or cachalot is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus Physeter and one of three extant species in the sperm whale family, along with the pygmy sperm whale and dwarf sperm whale of the genus Kogia.
The tucuxi, alternatively known in Peru bufeo gris or bufeo negro, is a species of freshwater dolphin found in the rivers of the Amazon basin. The word tucuxi is derived from the Tupi language word tuchuchi-ana, and has now been adopted as the species' common name. Despite being found in geographic locations similar to those of 'true' river dolphins such as the boto, the tucuxi is not closely related to them genetically. Instead, it is classed in the oceanic dolphin family (Delphinidae).
The grey seal is found on both shores of the North Atlantic Ocean. In Latin Halichoerus grypus means "hook-nosed sea pig". It is a large seal of the family Phocidae, which are commonly referred to as "true seals" or "earless seals". It is the only species classified in the genus Halichoerus. Its name is spelled gray seal in the US; it is also known as Atlantic seal and the horsehead seal.
Dall's porpoise is a species of porpoise endemic to the North Pacific. It is the largest of porpoises and the only member of the genus Phocoenoides. The species is named after American naturalist W. H. Dall.
The northern elephant seal is one of two species of elephant seal. It is a member of the family Phocidae. Elephant seals derive their name from their great size and from the male's large proboscis, which is used in making extraordinarily loud roaring noises, especially during the mating competition. Sexual dimorphism in size is great. Correspondingly, the mating system is highly polygynous; a successful male is able to impregnate up to 50 females in one season.
The rough-toothed dolphin is a species of dolphin that can be found in deep warm and tropical waters around the world.
The melon-headed whale, also known less commonly as the electra dolphin, little killer whale, or many-toothed blackfish, is a toothed whale of the oceanic dolphin family (Delphinidae). The common name is derived from the head shape. Melon-headed whales are widely distributed throughout deep tropical and subtropical waters worldwide, but they are rarely encountered at sea. They are found near shore mostly around oceanic islands, such as Hawaii, French Polynesia, and the Philippines.
A military marine mammal is a cetacean or pinniped that has been trained for military uses. Examples include bottlenose dolphins, seals, sea lions, and beluga whales. The United States and Soviet militaries have trained and employed oceanic dolphins for various uses. Military marine mammals have been trained to rescue lost naval swimmers, guard navy ships against enemy divers, locate mines for later clearance by divers, and aid in location and recovery of equipment lost on the seabed.
A marine mammal park is a commercial theme park or aquarium where marine mammals such as dolphins, beluga whales and sea lions are kept within water tanks and displayed to the public in special shows. A marine mammal park is more elaborate than a dolphinarium, because it also features other marine mammals and offers additional entertainment attractions. It is thus seen as a combination of a public aquarium and an amusement park. Marine mammal parks are different from marine parks, which include natural reserves and marine wildlife sanctuaries such as coral reefs, particularly in Australia.
The interactions between marine mammals and sonar have been a subject of debate since the invention of the technology.
Australian Mammalogy is a major peer-reviewed scientific journal published by CSIRO Publishing on behalf of the Australian Mammal Society covering research on the biology of mammals that are native or introduced to Australasia. Subject areas include, but are not limited to: anatomy, behaviour, developmental biology, ecology, evolution, genetics, molecular biology, parasites and diseases of mammals, physiology, reproductive biology, systematics and taxonomy.
The Society for Marine Mammalogy was founded in 1981 and is the largest international association of marine mammal scientists in the world.
Cetaceans form an infra-order of marine mammals. In 2020, approximately 86 species of cetaceans had been identified worldwide. Among these species, at least 35 have been sighted in the wider Caribbean region with very widespread distribution and density variations between areas. Caribbean waters are a preferred breeding site for several species of mysticeti, who live further north the rest of the year. The tucuxi and the boto live at the southern periphery of the Caribbean region in the freshwaters of the Amazon river and surrounding drainage basins.
