Elephants are the largest living land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae and the order Proboscidea; extinct relatives include mammoths and mastodons. Distinctive features of elephants include a long proboscis called a trunk, tusks, large ear flaps, pillar-like legs, and tough but sensitive grey skin. The trunk is prehensile, bringing food and water to the mouth and grasping objects. Tusks, which are derived from the incisor teeth, serve both as weapons and as tools for moving objects and digging. The large ear flaps assist in maintaining a constant body temperature as well as in communication. African elephants have larger ears and concave backs, whereas Asian elephants have smaller ears and convex or level backs.
Ivory is a hard, white material from the tusks and teeth of animals, that consists mainly of dentine, one of the physical structures of teeth and tusks. The chemical structure of the teeth and tusks of mammals is the same, regardless of the species of origin, but ivory contains structures of mineralised collagen. The trade in certain teeth and tusks other than elephant is well established and widespread; therefore, "ivory" can correctly be used to describe any mammalian teeth or tusks of commercial interest which are large enough to be carved or scrimshawed.
Proboscidea is a taxonomic order of afrotherian mammals containing one living family (Elephantidae) and several extinct families. First described by J. Illiger in 1811, it encompasses the elephants and their close relatives. Proboscideans include some of the largest known land mammals. The largest land mammal of all time may have been a proboscidean; the elephant Palaeoloxodon namadicus has been estimated to be up to 5.2 m (17.1 ft) at the shoulder and may have weighed up to 22 t, surpassing the paraceratheres, the otherwise largest known land mammals, though this estimate was made based on a single fragmentary femur and is speculative. The largest extant proboscidean is the African bush elephant, with a record of size of 4 m (13.1 ft) at the shoulder and 10.4 t. In addition to their enormous size, later proboscideans are distinguished by tusks and long, muscular trunks, which were less developed or absent in early proboscideans.
The walrus is a large pinniped marine mammal with discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. It is the only extant species in the family Odobenidae and genus Odobenus. This species is subdivided into two subspecies: the Atlantic walrus, which lives in the Atlantic Ocean, and the Pacific walrus, which lives in the Pacific Ocean.
The narwhal, also known as the narwhale, is a species of toothed whale. It is a member of the Monodontidae family, and the only species in the genus Monodon. Adults typically average 3.95 to 5.5 m in length and 800 to 1,600 kg in weight. The most prominent feature of the species is an adult male's long single tusk that can reach lengths of up to 3.1 m (10 ft). Instead of having a dorsal fin, narwhals possess a shallower dorsal ridge. They are gregarious animals, and may associate in groups of up to 20 members. Carl Linnaeus scientifically described the species in 1758 in his work Systema Naturae.
Walrus ivory, also known as morse, comes from two modified upper canines of a walrus. The tusks grow throughout life and may, in the Pacific walrus, attain a length of one metre. Walrus teeth are commercially carved and traded; the average walrus tooth has a rounded, irregular peg shape and is approximately 5 cm in length.
A mastodon is any proboscidean belonging to the extinct genus Mammut. Mastodons inhabited North and Central America from the late Miocene up to their extinction at the end of the Pleistocene 10,000 to 11,000 years ago. Mastodons are the most recent members of the family Mammutidae, which diverged from the ancestors of elephants at least 25 million years ago. M. americanum, the American mastodon, is the youngest and best-known species of the genus. They lived in herds and were predominantly forest-dwelling animals. M. americanum is inferred to have had a browsing diet with a preference for woody material, distinct from that of the contemporary Columbian mammoth. Mastodons became extinct as part of the Quaternary extinction event that exterminated most Pleistocene megafauna present in the Americas, believed to have been caused by a combination of climate changes at the end of the Pleistocene and hunting by recently arrived Paleo-Indians, as evidenced by a number of kill sites where mastodon remains are associated with human artifacts.
Incisors are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight. Opossums have 18, whereas armadillos have none.
The North Sulawesi babirusa is a pig-like animal native to Sulawesi and some nearby islands in Indonesia. It has two pairs of large tusks composed of enlarged canine teeth. The upper canines penetrate the top of the snout, curving back toward the forehead. The North Sulawesi babirusa is threatened from hunting and deforestation.
Palaeoloxodon is an extinct genus of elephant. The genus originated in Africa during the Early Pleistocene, and expanded into Eurasia at the beginning of the Middle Pleistocene. The genus contains some of the largest known species of elephants, over 4 metres (13 ft) tall at the shoulders, including the African Palaeoloxodon recki, the European straight-tusked elephant and the South Asian Palaeoloxodon namadicus. P. namadicus has been suggested to be the largest known land mammal by some authors based on extrapolation from fragmentary remains, though these estimates are highly speculative. In contrast, the genus also contains many species of dwarf elephants that evolved via insular dwarfism on islands in the Mediterranean, some only 1 metre (3.3 ft) in height, making them the smallest elephants known. The genus has a long and complex taxonomic history, and at various times, it has been considered to belong to Loxodonta or Elephas, but today is usually considered a valid and separate genus in its own right.
Stegodon is an extinct genus of proboscidean, related to elephants. It was originally assigned to the family Elephantidae along with modern elephants but is now placed in the extinct family Stegodontidae. Like elephants, Stegodon had teeth with plate-like lophs that are different from those of more primitive proboscideans like gomphotheres and mammutids. The oldest fossils of the genus are found in Late Miocene strata in Asia, likely originating from the more archaic Stegolophodon, shortly afterwards migrating into Africa. While the genus became extinct in Africa during the Pliocene, Stegodon remained widespread in South, Southeast and East Asia until the end of the Pleistocene.
African elephants are members of the genus Loxodonta comprising two living elephant species, the African bush elephant and the smaller African forest elephant. Both are social herbivores with grey skin, but differ in the size and colour of their tusks and in the shape and size of their ears and skulls.
The babirusas, also called deer-pigs, are a genus, Babyrousa, in the swine family found in the Indonesian islands of Sulawesi, Togian, Sula and Buru. All members of this genus were considered part of a single species until 2002, the babirusa, B. babyrussa, but following that was split into several species. This scientific name is restricted to the Buru babirusa from Buru and Sula, whereas the best-known species, the north Sulawesi babirusa, is named B. celebensis. The remarkable "prehistoric" appearance of these mammals is largely due to the prominent upwards incurving canine tusks of the males, which pierce the flesh in the snout.
The Columbian mammoth is an extinct species of mammoth that inhabited the Americas as far north as the Northern United States and as far south as Costa Rica during the Pleistocene epoch. The Columbian mammoth descended from Eurasian mammoths that colonised North America during the Early Pleistocene around 1.5-1.3 million years ago, and later experienced hybridisation with the woolly mammoth lineage. The Columbian mammoth was among the last mammoth species, and the pygmy mammoths evolved from them on the Channel Islands of California. The closest extant relative of the Columbian and other mammoths is the Asian elephant.
Palaeoloxodon namadicus is an extinct species of prehistoric elephant known from the early Middle to Late Pleistocene of the Indian subcontinent, and possibly also elsewhere in Asia. The species grew larger than any living elephant, and some authors have suggested it to have been the largest known land mammal based on extrapolation from fragmentary remains, though these estimates are speculative.
The woolly mammoth is an extinct species of mammoth that lived during the Pleistocene until its extinction in the Holocene epoch. It was one of the last in a line of mammoth species, beginning with the African Mammuthus subplanifrons in the early Pliocene. The woolly mammoth began to diverge from the steppe mammoth about 800,000 years ago in East Asia. Its closest extant relative is the Asian elephant. The Columbian mammoth lived alongside the woolly mammoth in North America, and DNA studies show that the two hybridised with each other.
Stegotetrabelodon is an extinct genus of primitive elephantid from the Late Miocene to Early Pliocene of Africa, the Arabian Peninsula, and Italy.
The Togian babirusa, also known as the Malenge babirusa, is the largest species of babirusa. It is endemic to the Togian Islands of Indonesia, but was considered a subspecies of Babyrousa babyrussa until 2002. Compared to the better-known north Sulawesi babirusa, the Togian babirusa is larger, has a well-developed tail-tuft, and the upper canines of the male are relatively "short, slender, rotated forwards, and always converge". The Togian babirusa is omnivorous, feeding mainly on roots and fallen fruit but also worms and invertebrates. Unlike other pig species, the Togian babirusa does not root at the ground with its snout when foraging, but instead can be seen pawing at the ground to uproot plants.
Teeth are common to most vertebrates, but mammalian teeth are distinctive in having a variety of shapes and functions. This feature first arose among early therapsids during the Permian, and has continued to the present day. All therapsid groups with the exception of the mammals are now extinct, but each of these groups possessed different tooth patterns, which aids with the classification of fossils.
"Mammut" borsoni is an extinct species of mammutid proboscidean known from the Late Miocene to Early Pleistocene of Eurasia, spanning from western Europe to China. It is the last known mammutid in Eurasia, and amongst the largest of all proboscideans.
Skull of Babyrousa celebensis , showing long upward curving canine tusks
Tusks of a Wild boar
Odobenocetops , an extinct whale with a long single tusk
