A callosity is a type of callus, a piece of skin that has become thickened as a result of repeated contact and friction.
A callosity is a type of callus, a piece of skin that has become thickened as a result of repeated contact and friction.
All Old World monkeys, gibbons, and some chimpanzees have pads on their rears known as ischial callosities. [1] [2] The pads enable the monkeys to sleep sitting upright on thin branches, beyond reach of predators, without falling. Humans do not possess ischial callosities due to the gluteal muscles being large enough to provide the same cushioning. [3]
The ischial callosities are one of the most distinctive pelvic features which separates Old World monkeys from New World monkeys. [4]
In whales, callosities are rough, calcified skin patches found on the heads of the three species of right whales. Callosities are a characteristic feature of the whale genus Eubalaena . Because they are found on the head of the whale and appear white against the dark background of the whale's skin, they allow the reliable identification of individuals of the species.
The callosities themselves are grey, but their white appearance is due to large colonies of whale lice, whale barnacles and parasitic worms which reside on them. [5] [6] Young whales and diseased individuals are often infested with a different species of cyamid, which gives the callosities on those whales an orange hue rather than white. [7] Callosities arise naturally and are present even in late-term whale fetuses, although the work of lice digging into the surface of the skin may make them more jagged and hard over time.[ citation needed ]
Callosities are found on the upper surface of the whale's head: above the eyes, on the jawline and chin, and surrounding the blowholes. [7] Callosities form a unique pattern on every right whale and, although callosities which are overgrown break off, the patterns do not change over a lifetime. [5]
The evolutionary significance of callosities is unknown. Male right whales have a higher density of callosities than females. Males have been observed scratching one another with their callosities and it has been suggested by Payne & Dorsey (1983) that they are a sexually dimorphic feature, used for intra-specific sexual aggression. [8] That explanation is not entirely satisfactory, because it does not account for the appearance of callosities in females.[ citation needed ] It has also been proposed that the barnacles attached to callosities are important in helping fend off attacks by orcas. [9]
Baleen whales, also known as whalebone whales, are marine mammals of the parvorder Mysticeti in the infraorder Cetacea, which use keratinaceous baleen plates in their mouths to sieve planktonic creatures from the water. Mysticeti comprises the families Balaenidae, Balaenopteridae (rorquals), Eschrichtiidae and Cetotheriidae. There are currently 16 species of baleen whales. While cetaceans were historically thought to have descended from mesonychians, molecular evidence instead supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 million years ago.
Right whales are three species of large baleen whales of the genus Eubalaena: the North Atlantic right whale, the North Pacific right whale and the Southern right whale. They are classified in the family Balaenidae with the bowhead whale. Right whales have rotund bodies with arching rostrums, V-shaped blowholes and dark gray or black skin. The most distinguishing feature of a right whale is the rough patches of skin on its head, which appear white due to parasitism by whale lice. Right whales are typically 13–17 m (43–56 ft) long and weigh up to 100 short tons or more.
The southern right whale is a baleen whale, one of three species classified as right whales belonging to the genus Eubalaena. Southern right whales inhabit oceans south of the Equator, between the latitudes of 20° and 60° south. In 2009 the global population was estimated to be approximately 13,600.
Balaenidae is a family of whales of the parvorder Mysticeti that contains mostly fossil taxa and two living genera: the right whale, and the closely related bowhead whale.
The North Atlantic right whale is a baleen whale, one of three right whale species belonging to the genus Eubalaena, all of which were formerly classified as a single species. Because of their docile nature, their slow surface-skimming feeding behaviors, their tendencies to stay close to the coast, and their high blubber content, right whales were once a preferred target for whalers. At present, they are among the most endangered whales in the world, and they are protected under the U.S. Endangered Species Act and Marine Mammal Protection Act and Canada's Species at Risk Act. There are an estimated 356 individuals in existence in the western North Atlantic Ocean—they migrate between feeding grounds in the Labrador Sea and their winter calving areas off Georgia and Florida, an ocean area with heavy shipping traffic. In the eastern North Atlantic, on the other hand—with a total population reaching into the low teens at most—scientists believe that they may already be functionally extinct. Vessel strikes and entanglement in fixed fishing gear, which together account for nearly half of all North Atlantic right whale mortality since 1970, are their two greatest threats to recovery.
The mandrill is a large Old World monkey native to west central Africa. It is one of the most colorful mammals in the world, with red and blue skin on its face and posterior. The species is sexually dimorphic, as males have a larger body, longer canine teeth and brighter coloring. It is the largest monkey in the world. Its closest living relative is the drill, with which it shares the genus Mandrillus. Both species were traditionally thought to be baboons, but further evidence has shown that they are more closely related to white-eyelid mangabeys.
The gelada, sometimes called the bleeding-heart monkey or the gelada baboon, is a species of Old World monkey found only in the Ethiopian Highlands, living at elevations of 1,800–4,400 m (5,900–14,400 ft) above sea level. It is the only living member of the genus Theropithecus, a name derived from the Greek root words for "beast-ape". Like its close relatives in genus Papio, the baboons, it is largely terrestrial, spending much of its time foraging in grasslands, with grasses comprising up to 90% of its diet.
The Cercopithecinae are a subfamily of the Old World monkeys, which comprises roughly 71 species, including the baboons, the macaques, and the vervet monkeys. Most cercopithecine monkeys are limited to sub-Saharan Africa, although the macaques range from the far eastern parts of Asia through northern Africa, as well as on Gibraltar.
A whale louse is a crustacean of the family Cyamidae. Despite the name, it is not a true louse, but rather is related to the skeleton shrimp, most species of which are found in shallower waters. Whale lice are external parasites, found in skin lesions, genital folds, nostrils and eyes of marine mammals of the order Cetacea. These include not only whales but also dolphins and porpoises.
The Yucatán black howler, or Guatemalan black howler, is a species of howler monkey, a type of New World monkey, from Central America. It is found in Belize, Guatemala and Mexico, in and near the Yucatán Peninsula. It lives in evergreen, semideciduous and lowland rain forests. It is also known as the baboon in Belize, although it is not closely related to the baboons in Africa.
The mona monkey is an Old World monkey that lives in western Africa between Ghana and Cameroon. The mona monkey can also be found on the island of Grenada as it was transported to the island aboard slave ships headed to the New World during the 18th century. This guenon lives in groups of up to thirty-five in forests. It mainly feeds on fruit, but sometimes eats insects and leaves. The mona monkey has brown agouti fur with a white rump. Its tail and legs are black and the face is blue-grey with a dark stripe across the face. The mona monkey carries food in cheek pouches.
The black colobus, or satanic black colobus, is a species of Old World monkey belonging to the genus Colobus. The species is found in a small area of western central Africa. Black colobuses are large, completely covered with black fur, and like all other Colobus monkeys, do not have a thumb. The species has faced large declines in population due to habitat destruction and hunting by humans, and was consequently listed as Vulnerable on the IUCN Red List in 1994.
The ursine colobus, also known as the white-thighed colobus, Geoffroy's black-and-white colobus, or the white-thighed black-and-white colobus, is a West African species of primate in the family Cercopithecidae.
Whale barnacles are species of acorn barnacle that belong to the family Coronulidae. They typically attach to baleen whales, and sometimes settle on toothed whales. The whale barnacles diverged from the turtle barnacles about three million years ago.
The buttocks are two rounded portions of the exterior anatomy of most mammals, located on the posterior of the pelvic region. In humans, the buttocks are located between the lower back and the perineum. They are composed of a layer of exterior skin and underlying subcutaneous fat superimposed on a left and right gluteus maximus and gluteus medius muscles. The two gluteus maximus muscles are the largest muscles in the human body. They are responsible for movements such as straightening the body into the upright (standing) posture when it is bent at the waist; maintaining the body in the upright posture by keeping the hip joints extended; and propelling the body forward via further leg (hip) extension when walking or running.
The Sanje mangabey is a highly endangered Old World monkey of the white-eyelid mangabey group from the Eastern Arc Mountains in Tanzania. They are about 50–65 centimetres (20–26 in) in length, excluding the tail, and their body colour is greyish. Fruit makes up about 70% of their diet. They live in valley forests and on mountain slopes, but are mostly ground-dwelling, which makes them susceptible to hunting and poaching. Their habitat is being degraded, and the International Union for Conservation of Nature has assessed their conservation status as being "endangered".
Baboons are primates comprising the genus Papio, one of the 23 genera of Old World monkeys, in the family Cercopithecidae. There are six species of baboon: the hamadryas baboon, the Guinea baboon, the olive baboon, the yellow baboon, the Kinda baboon and the chacma baboon. Each species is native to one of six areas of Africa and the hamadryas baboon is also native to part of the Arabian Peninsula. Baboons are among the largest non-hominoid primates and have existed for at least two million years.
Sexual swelling, sexual skin, or anogenital tumescence refers to localized engorgement of the anus and vulva region of some female primates that vary in size over the course of the menstrual cycle. Thought to be an honest signal of fertility, male primates are attracted to these swellings; preferring, and competing for, females with the largest swellings.
Coronula diadema is a species of whale barnacle that lives on the skin of humpback whales and certain other species of whale. This species was first described by Carl Linnaeus in the 1767 12th edition of his Systema Naturae.