The Tana River red colobus (Procolobus rufomitratus), also called the eastern red colobus, is a highly endangered species of primate

Primate

A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...

 in the Cercopithecidae family. It is endemic to a narrow zone of gallery forest

Gallery forest

Gallery forests are evergreen forests that form as corridors along rivers or wetlands and project into landscapes that are otherwise only sparsely treed such as savannas, grasslands or deserts....

 near the Tana River

Tana River (Kenya)

The long Tana River is the longest river in Kenya, and gives its name to the Tana River District. Its tributaries include the Thika. The river rises in the Aberdare Mountains to the west of Nyeri. Initially it runs east before turning south around the massif of Mount Kenya. The river then runs...

 in southeastern Kenya

Kenya

Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...

. As all red colobus

Red colobus

Red colobuses are Old World monkeys of the subgenus Piliocolobus in genus Procolobus. Some authors elevate Piliocolobus to a full genus, limiting Procolobus to the olive colobus. They are closely related to the black-and-white colobus monkeys and some species are often found in groups with the...

es, it was formerly considered a subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of a widespread P. badius.

Conservation status

The Tana River red colobus has been considered one of The World's 25 Most Endangered Primates

The World's 25 Most Endangered Primates

The World's 25 Most Endangered Primates is a list of highly endangered primate species selected and published by the International Union for Conservation of Nature Species Survival Commission Primate Specialist Group , the International Primatological Society , and Conservation International...

. It was, together with the equally endangered Tana River mangabey

Tana River Mangabey

The Tana River mangabey is a highly endangered species of primate in the Cercopithecidae family. Some authorities have included the taxa agilis and sanjei as subspecies of this species, while others award these full species status.It is endemic to riverine forest patches along the lower Tana River...

, the main reason for the creation of the Tana River Primate Reserve

Tana River Primate Reserve

Tana River Primate Reserve, totaling eleven square miles of scattered forest patches, was set aside in 1976 in order to protect the swampy forests of the Lower Tana River and two endangered primates, the Tana River Mangabey and the Tana River Red Colobus, that are found there.The reserve,...

 in 1978, but human encroachment within this reserve continues. Recently, it has been suggested that 20,000 hectares of the Tana River Delta should be transformed into sugarcane plantations, but this has, temporarily at least, been stopped by the High Court of Kenya. Contra Groves

Colin Groves

Colin Peter Groves is Professor of Biological Anthropology at the Australian National University in Canberra, Australia.Born in England on 24 June 1942, Colin Groves completed a Bachelor of Science at University College London in 1963, and a Doctor of Philosophy at the Royal Free Hospital School of...

, it was not recognized as a species separate from the Ugandan

Ugandan Red Colobus

The Ugandan red colobus is a species of red colobus monkey found in forests of Uganda, Rwanda, Burundi and western Tanzania. It has been considered a subspecies of P. badius, and later a subspecies of P. foai. It was recognised as a distinct species by Groves in 2001, while others have suggested...

, Central African

Central African Red Colobus

The Central African red colobus is an Old World monkey in the Cercopithecidae family. It is found in humid forests in the Democratic Republic of Congo, the Republic of the Congo, the Central African Republic, and Sudan.-Taxonomy:...

 and Thollon's red colobus

Thollon's Red Colobus

Thollon's red colobus , also known as the Tshuapa red colobus, is a species of red colobus monkey from the Democratic Republic of the Congo and lower Republic of the Congo. It is found south of Congo River and west of Lomami River. It had once been considered a subspecies of the P. badius...

 in the 2008 IUCN Red List. With these as subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

, P. rufomitratus is considered to be of least concern

Least Concern

Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...

in the 2008 IUCN Red List, while P. (r.) rufomitratus is considered endangered.

Diet

Colobus monkeys eat mostly leaves from a limited number of tree species. They supplement this bulky cellulose diet with occasional unripe fruit, moss and seeds. Human food is of no interest to these leaf specialists. Their stomach is large and has three chambers. It carries a specific bacterium which helps to ferment and digest the leaves. They eat about 2 or 3 kilograms of leaves a day. Sometimes they eat soil, clay and charcoal to help digest toxins and toxic leaves. Because of the poor nutritional quality of their food they must browse intensively for many hours each day looking for food, and spend much of the remainder of the day resting in order to aid digestion.