Cotton-top tamarin

The cotton-top tamarin (Saguinus oedipus) is a small New World monkey weighing less than 0.5 kg (1.1 lb). One of the smallest primates, the cotton-top tamarin is easily recognized by the long, white sagittal crest extending from its forehead to its shoulders. The species is found in tropical forest edges and secondary forests in northwestern Colombia, where it is arboreal and diurnal. Its diet includes insects and plant exudates, and it is an important seed disperser in the tropical ecosystem. The cotton-top tamarin displays a wide variety of social behaviors. In particular, groups form a clear dominance hierarchy where only dominant pairs breed. The female normally gives birth to twins a...

The cotton-top tamarin has a diet of mainly fruit (40%) and animal material (40%). This includes insects, plant exudates such as gum and sap, nectar, and occasionally reptiles and amphibians. Due to its small body size and high food passage rate, its diet must be high-quality and high-energy. Insectivory is common in the cotton-top and the species hunts for insects using a variety of methods: stealth, pouncing, chasing, exploring holes, and turning over leaves. Tamarins act as seed dispersers in tropical ecosystems. While larger primates eat larger seeds, tamarins eat the smaller ones. The expelled seeds have a higher germination rate than others and ingesting larger seeds may help to dislodge and expel intestinal parasites. The cotton-top tamarin is diurnal and sleeps with its social group in trees with foliage cover. The group leaves the sleeping tree together an hour after dawn and spends the day foraging, resting, travelling, and grooming. The species is thought to rise late and increases the speed of its foraging and travelling before dusk to avoid crepuscular and nocturnal predators. Its main predators include raptors, mustelids, felids, and snakes. The cotton-top tamarin is extremely vigilant, always looking for potential predators. When the group is resting, one individual moves apart and acts as a lookout to alert the group if it sees a threat. The cotton-top tamarin can live as long as 24 years in captivity, while its lifespan in the wild averages 13 years.

Colombia

The cotton-top tamarin is a highly social primate that typically lives in groups of two to nine individuals, but may reach up to 13 members. These small familial groups tend to fluctuate in size and in composition of individuals and a clear dominance hierarchy is always present within a party. At the head of the group is the breeding pair. The male and female in this pair are typically in a monogamous reproductive relationship, and together serve as the group's dominant leaders. Dominant pairs are the only breeding pair within their groups, and the female generally has authority over the breeding male. While nonbreeding group members can be the leading pair's offspring, immigrant adults may also live with and cooperate in these groups. This social grouping in cotton-top tamarins is hypothesized to arise from predation pressure. Cotton-top tamarins exhibit prosocial behavior that benefits other members of the group, and are well known for engaging in cooperative breeding whereby the group's subordinate adults help in rearing the offspring of the dominant pair. The dominant female is more likely to give birth to non-identical twins than a singleton, so it would be too energetically expensive for just one pair to raise the young. To prevent younger, subordinate females within the group from breeding, the dominant female uses pheromones. This suppresses sexual behavior and delays puberty. Unrelated males that join the group can release the females from this reproductive suppression; this may result in more than one female of the group becoming pregnant, but only one of the pregnancies will be successful. ==== Cooperation ==== In cooperative breeding, the effort put into caring for the dominant breeders' offspring is shared by the group members. Parents, siblings, and immigrant adults share young rearing duties for the breeding pair's young. These duties include carrying, protecting, feeding, comforting, and even engaging in play behavior with the group's young. Cotton-top tamarins display high levels of parental investment during infant care. Males, particularly those that are paternal, show greater involvement in caregiving than do females. The father usually begins carrying their newborns on their day of birth. They spend as much time caring for newborns as the mother does during the first 5 days after birth. The sons and daughters of the family will delay emigration in order to care for the infant as well. Despite this, both male and female infants prefers contact and proximity to their mothers over their fathers. Males may invest additional support in rearing offspring as a form of courtship to win the favor of the group's dominant female. However, evidence indicates that time spent carrying infants does not correlate with a male's overall copulation frequency. Since only one female in a group breeds, heavy investment in infant care ensures that all offspring survive until independence. Accordingly, cotton-top tamarins bear excessive costs to care for the group's young. Male carriers, especially paternal carriers, incur large energetic costs for the sake of the group's young. This burden may cause some male cotton-tops to lose up to 10–11% of their total body weight. The large weight loss may occur from reduced food intake as infant-carrying inhibits foraging ability for a carrier. The trend of male-carrier weight loss and decreased food intake is in contrast to the dominant female's periovulatory period, when she gains weight after increasing her own food intake and relinquishing much of her infant-carrying duties. ==== Altruism ==== While caregiving by males appears to be altruistic, particularly in cotton-top sires, the costs of infant care may in fact be tolerated for selfish reasons. Namely, the costs to male weight and foraging ability may, in turn, promote consecutive pregnancies in dominant females, thereby providing more offspring bearing the sire's genes. Additionally, the cooperative breeding structure of cotton-to…

longest observed 26.2 years.

The cotton-top tamarin is part of the most diminutive family of monkeys, Callitrichidae, the marmosets and tamarins; it weighs 432 g (15.2 oz) on average. Its head–body length is 20.8–25.9 cm (8.2–10.2 in), while its tail—which is not prehensile—is slightly longer at around 33–41 cm (13–16 in). The species is not sexually dimorphic, the male and female are of a similar size and weight. Members of the Callitrichinae subfamily (including this species) have sharp nails (tegulae) on all digits except the big toes, which have the flat nails (ungulae) common to other primates. Tegulae resemble a squirrel's claws and help with movement through trees. The cotton-top tamarin has a long sagittal crest, consisting of white hairs, from forehead to nape flowing over the shoulders. The skin of the face is black with gray or white bands located above the eyes. These bands continue along the edge of the face down to the jaw. Tamarins are generally divided into three groups by their facial characteristics: hairy-faced, mottled-faced, and bare-faced. The cotton-top tamarin has fine white hair covering its face, but they are so fine as to appear naked, thus it is considered a bare-faced tamarin. Its lower canine teeth are longer than its incisors, creating the appearance of tusks. Like other callitrichids, the cotton-top tamarin has two molar teeth on each side of its jaw, not three like other New World monkeys. The cotton-top tamarin has fur covering all of the body except the palms of the hands and feet, the eyelids, the borders of the nostrils, the nipples, the anus, and the penis. The back is brown, and the underparts, arms, and legs are whitish-yellow. The rump and inner thighs and upper tail are reddish-orange. The fur is distributed with varying densities throughout the body: the genital region (scrotum and pubic zone), axilla, and the base of the tail have lower densities, while the forward region is much higher. Many individuals have stripes or whorls of fur of striking coloration on their throats. The cotton-top also has whiskers on its forehead and around its mouth.

The wild population is estimated at 6,000 individuals, with 2,000 adults. This species is critically endangered, and was listed in "The World's 25 Most Endangered Primates between 2008 and 2012." The publication lists highly endangered primate species and is released every two years by the International Union for Conservation of Nature Species Survival Commission Primate Specialist Group. The cotton-top tamarin was not selected for the 2012–2014 publication. Habitat destruction through forest clearing is the main cause of this collapse, and the cotton-top has lost more than three-quarters of its original habitat to deforestation, while the lowland forest in which it lives has been reduced to 5% of its historical range. This land is then used for large-scale agricultural production (i.e. cattle) and farming, logging, oil palm plantations, and hydroelectric projects that fragment the cotton-top tamarin's natural range. The illegal pet trade and scientific research have also been cited as factors by the IUCN. While biomedical studies have recently limited their use of this species, illegal capture for the pet trade still plays a major role in endangering the cotton-top. Before 1976, when CITES listed the species under Appendix I banning all international trade, the cotton-top tamarin was exported for use in biomedical research. In captivity, the cotton-top is highly prone to colitis, which is linked to an increased risk of a certain type of colon cancer. Up to 40,000 individuals were caught and exported for research into those diseases, as well as Epstein–Barr virus, for the benefit of humans. The species is now protected by international law. Although enough individuals are in captivity to sustain the species, it is still critically endangered in the wild. The Proyecto Tití ("Project Tamarin") was started in 1985 to provide information and support in conservation of the cotton-top tamarin and its habitat in northern Colombia. Proyecto Tití's programs combine field research, education, and community programs to spread awareness about this endangered species and encourage the public to participate in its protection. It now has partner status with the Wildlife Conservation Network.

S. oedipus has the common names "cotton-top tamarin" and "cotton-headed tamarin" in English. Its name comes from the white hair that spans its head and flows down past the neck. In Spanish, it is commonly called bichichi, tití pielroja, tití blanco, tití cabeza blanca, or tití leoncito. In German-speaking areas, the cotton-top tamarin is commonly known as Lisztaffe (literally "Liszt monkey") due to the resemblance of its crest to the hairstyle of Hungarian composer and piano virtuoso Franz Liszt. The species was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae. as Simia oedipus. Linnaeus chose the specific name oedipus, which means swollen foot, but as the species does not have particularly large feet, it is unknown why he chose this name. (Linnaeus often selected names from mythology without any particular rationale, and he may have used the name of Oedipus, the mythical Greek king of Thebes, more or less arbitrarily.) In 1977, Philip Hershkovitz performed a taxonomic analysis of the species based on fur coloration patterns, cranial and mandibular morphology, and ear size. He classified Geoffroy's tamarin S. geoffroyi as a subspecies of S. oedipus. Subsequent analyses by Hernández-Camacho and Cooper (1976), Russell Mittermeier and Coimbra-Filho (1981), and later Grooves (2001) consider the S. oedipus and S. geoffroyi types to be separate species. Some researchers, such as Thorington (1976), posit that S. oedipus is more closely related to the white-footed tamarin (S. leucopus) than to S. geoffroyi. This view is supported by Hanihara and Natoria's analysis of toothcomb dental morphology (1987) and by Skinner (1991), who found similarities between S. oedipus and S. leucopus in 16 of 17 morphological traits considered. This species of white-headed tamarin is thought to have diverged from the other Amazonian forms such as S. leucopus. This is supported by morphological considerations of the transition from juvenile to adulthood, during which the fur coloration patterns change. significantly and are similar between the two species. Hershkovitz proposed that the separation of the two species happened in the Pleistocene at the height of the Atrato River, where it intersected the Cauca-Magdalena. At that time, the area was covered by a sea, which created a geographic barrier that caused the species to diverge through the process of allopatric speciation. Today, the two species are principally separated by the Atrato River. In 2022, Jeferson Carneiro and his colleagues proposed the designation of the genus Oedipomidas as part of a taxonomic reclassification effort for New World tamarins and marmosets. Under this designation, the cotton-top tamarin could be reclassified as O. oedipus, with Saguinus being resorted to a synonym as a result.