iPhoneOgraphy – 17 Oct 2016 (Day 291/366)
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 dispenser 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 and uses pheromones to prevent other females in the group from breeding. These tamarins have been extensively studied for their high level of cooperative care, as well as altruistic and spiteful behaviors. Communication between cotton-top tamarins is sophisticated and shows evidence of grammatical structure, a language feature that must be acquired.
Up to 40,000 cotton-top tamarins are thought to have been caught and exported for use in biomedical research before 1976, when CITES gave them the highest level of protection and all international trade was banned. Now, the species is at risk due to large-scale habitat destruction, as the lowland forest in northwestern Colombia where the cotton-top tamarin is found has been reduced to 5% of its previous area. It is currently classified as critically endangered and is one of the rarest primates in the world, with only 6,000 individuals left in the wild.
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”) most likely due to the resemblance of its hairstyle with that of Hungarian composer and piano virtuoso Franz Liszt.
The species was first described by Linnaeus in 1758 as Simia oedipus. Linnaeus chose the species 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), 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 tooth comb 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.