Patas monkey
Erythrocebus patas

TAXONOMY

Suborder: Haplorrhini
Infraorder: Simiiformes
Superfamily: Cercopithecoidea
Family: Cercopithecidae
Subfamily: Cercopithecinae
Genus: Erythrocebus
Species: patas

Other names: Patas, red guenon, red monkey, military monkey, nisnas, Aïr patas, Aïr red, black-nosed patas, west African patas, west African red monkey, blue nile hussar monkey, dancing red monkey, nile patas, Ikoma patas or red hussar monkey; engabwor (Ateso); cercopitheque patas, le singe rouge, patas (French); husarenaffe (German); elwala (Karamajong); naggawo (Luganda); ayom (Lwo); akahinda (Runyoro); husarapa or patasapa (Swedish).

Traditionally, only one species of patas monkey has been recognized but up to four subspecies have been proposed, E.p.baumstarki, E.p.patas, E.p.pyrrhonotus, E.p.villiersi. These subspecies are disputed and may only represent geographical divisions of the species (see Groves 2001; Grubb et al. 2003).

MORPHOLOGY

Photo: Anne & Ron Carlson

Patas monkeys are a slender species colored red-brown dorsally and grey-white ventrally (Rowe 1996). The face can be recognized by a black brow ridge and nose as well as by the white area around the mouth (Loy 1974). Adult E. p. pyrrhonotus have a white nose, changing from black as they approach sexual maturity (K. Enstam, pers. comm.). During pregnancy, the facial hair of female patas monkeys noticeably lightens, potentially as a result of changing hormone levels (Palmer et al. 1981). Males possess a bright blue scrotum (Groves 2001; Rowe 1996). Patas exhibit a large degree of sexual dimorphism with adult males weighing 12.4 kg (27.3 lb) and adult females weighing 6.5 kg (14.3 lb) on average (Galat-Luong et al. 1996). The patas male measures, excluding the tail, 600 to 875 mm (23.6 to 34.4 in) and the female measures 490 mm (19.3 in) on average (Rowe 1996). The maximum recorded longevity for a patas monkey in the wild is 21.6 years (Ross 1991).

Patas monkeys are physically adapted for life on the ground. Their slender bodies and long limbs are morphologically suited for terrestrial movement and speed rather than for arboreal movement (Gartlan 1974). Patas monkeys are quadrupedal and their terrestrial locomotion is extremely quick for a primate, with a maximum speed of approximately 55 km per hour (34.2 mph) reported (Hall 1965). Their especially long forelimbs facilitate this high running speed which provides an avenue of escape from predators (Etter 1973). In addition, they will occasionally assume a bipedal stance when alarmed, and can move bipedally if carrying an item in both hands (Hall 1965). The tail curves down while on the ground, but is raised when on a narrow surface such as a tree branch, most likely for balance (Hall 1965; Hall et al. 1965). When descending, the tail performs as a brace and controls the monkey's descent (Hall et al. 1965; Struhsaker & Gartlan 1970).

RANGE

Patas monkeys occur in a broad band across central Africa, between the Sahara in the north and the equatorial rain forests in the south (Chism & Rowell 1988). They occur from Senegal on the west coast of Africa all the way east to the Sudan and south to Lake Tanganyika, one of Africa's Great Lakes (Tappen 1960). Kenya, the Congo, the Central African Republic, Cameroon and northern Tanzania form the southern border of the patas' range. To the north, their range extends into Mauritania, Mali, Niger, and Chad (Rowe 1996). There is some debate as to the easternmost extent of their territory with some extending their range into Somalia (Kingdon 1971). Other countries in the patas range include Benin, Burkina Faso, Côte d'Ivoire, Ethiopia, the Gambia, Ghana, Guinea, Guinea-Bissau, Nigeria, Sierra Leone, Togo, and Uganda. Within their range, populations are sometimes spotty with gaps where no patas are to be found, however the greatest population densities are in west central Africa (Gartlan pers. comm. cited in Wolfheim 1974).

An artificially introduced population of patas in Puerto Rico was brought to the locality for research by the Caribbean Primate Research Center in the 1960s (Gonzalez-Martinez 1998). This population is allowed to be free-ranging and a number of individuals migrated to mainland Puerto Rico where a breeding population of unknown size lives (Gonzalez-Martinez 1998).

E. patas range (in red)

The first study of wild patas monkeys was undertaken by K.R.L. Hall in Uganda during the 1960s. Since, there have been several other studies of wild and semi-wild patas in Cameroon, Kenya and Puerto Rico, in addition to a number of captive studies. Other notable patas researchers include Janice Chism, Karin Enstam, Lynne Isbell, and Naofumi Nakagawa.

HABITAT

Open country is the domain of the patas monkey, but they adapt well and tolerate several types of habitat (Tappen 1960). The patas monkey habitat can range from savanna and steppe to woodland and thorn scrub, and from true desert to relatively moist areas (Hall 1965, Chism et al. 1984). The patas monkey prefers wide open areas and ventures only into those woodlands near open areas (Gartlan, pers. comm. 1974 cited in Wolfheim 1983). In one study, patas were demonstrated to prefer grassland in the wet season and they preferred to sleep in woodlands to avoid predators (Nakagawa 1999). Their habitat can also be classified as having moderate to low rainfall and marked dry seasons (Hall 1965, Gartlan 1974). When offered a choice between short and tall trees, patas monkeys prefer taller trees and spend more of their time in them (Enstam and Isbell 2004).

Patas have been studied in three discrete areas of their broad range, Uganda, Kenya and Cameroon. Ugandan patas are found in a range of vegetation zones including steppe, woodland, thicket, and grass and wooded savanna (Hall 1965). Within this area of patas occupation is a great variety of climate and vegetation ranging from a dichotomy of hot, dry winters and rainy summers to areas where it can rain year-round. As a result, the rainfall totals for the Uganda patas habitat vary quite a bit also, from 500 to 1250 mm (19.7 to 49.2 in) per year on average (Hall 1965). The Kenyan habitat, near the southeastern end of their range, contains patas populations that were observed to reside in areas anywhere from treeless grassland to dense woodland to savanna woodland. Rainfall in these areas averaged 630 mm (24.8 in) per year with the most rain falling between April and November and the least in January (Chism & Rowell 1988). In Cameroon, the patas monkey has been studied in the African Sahel, a semi-desert ecosystem with annual rainfall of less than 508 mm (20 in) and a prolonged dry season (Tappen 1960). The most important trait of the Sahel is its precipitation which is low and seasonal (Gartlan 1974). The water sources in the Sahel areas are vitally important for all of the mammals living there, including the patas monkey. A patas must drink two or three times a day during the dry season (Gartlan 1974).

ECOLOGY

The patas monkey's diet varies with changes in food availability due to the seasonality of its environment. It is most aptly described as omnivorous, relying on plant material, insects, and animal material for sustenance. During the rainy season, it will eat plant materials including fruits, flowers, leaves, stems and gums as well as insects, other animal material, and fungi (Nakagawa 1989; Hall 1965). It is suggested that their rainy season diet choice reflects the life cycle of the plants on which they rely which produce fruit and berries during this time (Nakagawa 1989). Patas do the majority of their feeding on the ground, with up to 85% of feeding activity occurring terrestrially (Gartlan 1974). Also of importance to the patas is the inclusion of insects in their diet, as evidenced by the relatively high expenditure of foraging time to obtain them. Grasses play a surprisingly unimportant dietary role as one would expect a resource as available as grass to comprise at least some part of patas subsistence (Chism & Rowell 1988). In one study in Kenya, the patas diet was observed to be almost two-thirds gum and arthropods, which would make them by far the physically largest primarily exudativorous or insectivorous primate (Isbell 1998). Patas have been observed catching and eating lizards and even robbing eggs from the nests of birds in trees (Hall 1965). Further, patas will take immature weaver bird chicks from their nests and eat them (K. Enstam, pers. comm.). There are also instances in which patas were observed catching and eating fish out of evaporating natural pools in Senegal (Galat-Luong 1991). In habitats near cultivated areas, there is a high instance of crop-raiding by patas (Chism & Rowell 1988).

Photo: Anne & Ron Carlson

Daily patas activity can be divided into two main activity periods, one in the morning and one in the afternoon, divided by a roughly one-to-two hour resting period around midday (Hall 1965; Nakagawa 1989). During the morning and afternoon activity periods, time is spent feeding, grooming, and on social activities, with grooming and social activities mostly taking place in the morning and the resting period (Hall 1965). Overnight, the patas stay in sleeping trees, preferring to sleep one individual per tree, except in the case of mothers with infants who will remain together (Chism et al. 1983). This behavior reduces the risk of predation and assists with concealment as it is difficult to see one individual in the crown of a tree (Chism et al. 1983). Typically, patas will not sleep in the same tree for two consecutive nights but this may only be in areas where the predation risk is high, as sleeping-tree sharing among several individuals in the same night has been observed in wild populations in Cameroon (Nakagawa 1999). The daytime patas anti-predation strategy has three aspects, consisting of crypsis, watchfulness, and speed (Chism 1999). Potential predators of the patas monkey include dogs, humans, felids, hyenas, raptors and possibly baboons (Chism et al. 1983; Chism & Rowell 1988; Enstam & Isbell 2002).

Because patas habitat is marked by seasonality between dry and wet seasons, patas behavior changes accordingly between these seasons in relation to their proximity and usage of available water. Overall, wet season observations of Ugandan patas recorded markedly rare drinking behaviors (Hall 1965). During the dry season however, patas were observed congregating around remaining water sources, and the staying nearby and incidence of drinking and agonistic behavior between groups increased considerably (Struhsaker & Gartlan 1970).

The home range and daily path length of the patas monkey can vary considerably among different groups at different locations. In Uganda, the patas home range was estimated to be 52 km² (20.1 mi²) and the daily path to be .7 km to 11.8 km (.43 to 7.33 mi) (Hall 1965). In Kenya, the patas home range was observed to be 23.4 km² to 32 km² (9.03 to 12.36 mi²) and their daily path was 3.83 km to 4.22 km (2.38 to 2.62 mi) (Chism and Rowell 1988). Cameroonian observations put the home range at 2.66 to 4.4 km² (1.03 to 1.7 mi²) (Nakagawa 1999). This significant variation may be due to patas behavior changing with the seasons and the available water supply. It has been suggested that the reason that patas move more than many Old World Monkeys and the reason why their morphology is so well suited to movement, is their diet, which is widely dispersed but high in quality (Isbell 1998).

Content last modified: December 18, 2006

Written by Kurt Gron. Reviewed by Karin Enstam.

Cite this page as:
Gron KJ. 2006 December 18. Primate Factsheets: Patas monkey (Erythrocebus patas) Taxonomy, Morphology, & Ecology. <http://pin.primate.wisc.edu/factsheets/entry/patas_monkey>. Accessed 2008 May 9.