PATAS MONKEY

Erythrocebus patas

Geographic Distribution and Habitat

Patas monkeys—also known as hussar monkeys, wadi monkeys, nisnas, and singe rouge—are monkeys of the Cercopithecidae family. They are found north of Africa’s equatorial forests and south of the Sahara Desert, with a distribution ranging from western Senegal to Kenya and northern Tanzania, although they are found at highest density in West Africa. They have a preference for open savannah woodland, but can also be found in a wider range of habitats.

Across its widely distributed range of 24 counties, three subspecies are recognized:

  • The western patas monkey (Erythrocebus p. patas) resides north of the equatorial forests and south of the Sahara from western Senegal and The Gambia, southern Mauritania, southern Mali, Guinea Bissau to eastern Nigeria and southern Chad, and possibly into northeastern Chad.
  • The eastern patas monkey (Erythrocebus p. pyrrhonotus) occurs north of the equatorial forests and south of the Sahara from southeastern Chad eastwards through Central African Republic, northern Democratic Republic of Congo, South Sudan, and central and southern Sudan, southeastwards to northern Uganda to northwestern and central Kenya.
  • The Aïr patas monkey (Erythrocebus p. villiersi) is endemic to the Aïr Massif, central northern Niger, where it occurs in several isolated pockets, but mainly in the larger valleys in the south.

An introduced population of patas monkeys lives in Puerto Rico, US. They were intentionally released on Cueva Island and Guayacan Island between 1971 and 1981 by the La Parguera Primate Facility. Between 1974–1981 individuals have gradually migrated from the islands to mainland Puerto Rico and formed free ranging population groups, where they are considered a nuisance species.

TAXONOMIC UPDATES

Two other patas monkeys species are recognized. We mention them here because, at this juncture, there are not enough data about one of the species to warrant its own profile and the other is on the brink of extinction. Until recently, all patas monkeys were considered to be a single species. However more sophisticated scientific analysis and better understanding of their geographic distributions and morphological differences means that three distinct species of patas monkeys are now recognized under the genus Erythrocebus. The other two are:

  • Heuglin’s patas monkey (E. poliophaeus) endemic to Ethiopia, Sudan, and possibly South Sudan. Little data are available about this species. (No range map is available.)
  • The Critically Endangered southern patas monkey (E. baumstarki) with only 40–100 mature individuals remaining in the wild, they are found in northern Tanzania and are extinct in Kenya. (Range map is included below.)
Patas monkey overall geographic range, IUCN 2020.
Southern patas monkey range, IUCN 2020

Size, Weight, and Lifespan

With a body length of 25–35 in (61–89 cm) and a tail length of 20–30 in (51–76 cm), patas monkeys can be considered a medium-to-large size for the Cercopithecidae family (monkeys found in Africa and Asia). Compared to other primates, they have long limbs and a slim body, perfectly adapted to running across the savannah. They also have larger canines, proportional to their size, than any other primate.

These monkeys display sexual dimorphism; the males are generally larger than the females, and weigh between 15 and 29 lbs (6.8–13.2 kg), whereas females weigh between 9 and 15 lbs (4.1–6.8 kg).

Their lifespan in the wild is around 15–20 years, but in captivity, due to plentiful food, veterinary care, and a lack of predators, this can increase to 21–24 years.

Appearance

Patas monkeys are a colorful primate and their pelage can help distinguish between species. In general, patas monkeys have a thick red-brown pelage that turns white around their legs and belly and becomes darker around the shoulders. They have dark faces, framed by white hair and both sexes sport impressive white moustaches, though the males’ moustaches tend to be thicker and longer. The crown of their heads is a reddish-brown and they have thick, mane-like hair around the neck and shoulders. Male patas monkeys have a blue scrotum, similar to that of vervet monkeys.

A key morphological difference between the species is that the patas monkeys in the species Erythrocebus patas (simply called “patas monkeys”) have a white nose, whereas the other two species have black noses. Additionally, the other two species tend to have a darker, almost black pelage around the shoulders and the ventral side is more pinkish than white. Like many other African monkeys, infants are born with pinkish faces that darken as they age, as well as a pale brown coat. 

​Diet

Patas monkeys are omnivorous and therefore feed on both plant and animal matter. Their diet primarily consists of gum from acacia trees (Acacia drepanolobium), as well as arthropods and other animals, such as grasshoppers, weevils, and even birds. Interestingly, this is a diet usually associated with smaller-bodied primates, but it is thought that, because these food sources are so easily found in their habitats, they are able to survive on them. While historically they rarely came into conflict with humans, the rise in the human population has led farmers to convert the patases’ dry woodland home into land for agriculture. This habitat modification has led patas monkeys to engage in crop raiding in several areas throughout their range, and they are known to raid crops such as wheat, millet, and bananas.

Behavior and Lifestyle

Patas monkeys travel long distances each day. They are mostly terrestrial and walk or run using all four limbs. Luckily, their long limbs allow them to travel these long distances without exerting too much energy. In fact, their long limbs, slim body, and short digits make them extremely fast runners. They are the fastest primate in the world. When running to escape predators, patas monkeys can reach speeds of up to 34.2 miles (55 km) per hour! As comparison, the world’s fastest human can reach a top speed of just over 27 miles per hour (44km) per hour. 

Patas monkeys need to drink water every day. Their daily movements are often heavily influenced by their search for water. Their large home ranges can vary from 14 square miles (23 sq km) to an impressive 50 square miles (80 sq km) and can be up to 100 times larger than the home ranges of the sympatric vervet monkey

Although primarily terrestrial, at night they sleep together in trees to keep safe from predators.

Fun Facts

​Patas monkeys are the fastest primates in the world, reaching speeds of up to 34 miles per hour (55 km/hr).

They live in single-male groups, but females still mate with extra-group males.

They have a very high reproductive rate, with females usually having their first infant at three years of age. 

Daily Life and Group Dynamics 

Female patas monkeys are philopatric, meaning that they stay in the group they were born into their entire lives, whereas males leave the group when they become adults (around three years of age). Groups can vary between approximately 9-40 members. 

Each group has only one resident male who often manages to stay in the group for only a year or less. Males compete with one another year round for control of the group and these conflicts can reach a high intensity until the loser is forced from the group.

Unlike some other monkeys who live in female-resident social groups, patas females don’t have a very stable dominance hierarchy—it is not uncommon for a female considered lower ranking to win a fight with a female considered higher ranking. They do sometimes form coalitions, though this is fairly rare. It is thought that this fairly weak hierarchy is because their food is widespread and therefore fights over food are not that common.

Communication

The patas monkey communicates via a number of modalities, including vocal and non-vocal. They have a wide repertoire of facial expressions and bodily postures used in a range of settings, including the threatening open-mouth stare and the submissive crouching posture. They also produce a number of vocalizations across contexts, including specific alarm calls to warn the troop which predator is approaching, and screams or moans during conflicts.

Females often display a special combination of locomotion, facial expression, and vocalization, including puffed up cheeks and a half-crouching run, when they are soliciting a male for mating. This combination of vocal and gestural communication is common in primates and scientists have yet to fully understand the wide range of gestural communication that many species engage in.

Reproduction and Family

While there is generally only one resident male per group, extra-group males often enter the group during mating season and succeed in mating with females. Infanticide (killing of infants) is rare in this species, but males have been documented killing infants that were conceived before their tenure as resident male.

Compared to other monkeys, female patas monkeys have extremely high reproductive rates; they generally start reproducing at just three years of age and usually have one infant every following year. Allomothering occurs in patas monkeys; non-mother females may carry, groom, or otherwise handle an infant. There is often an exchange whereby other females will groom the mother in return for being permitted to handle the infant. The result is that mothers receive more grooming when they have an infant than at other times of the year. Allomothering can help juvenile females or females without infants to practice their mothering skills and infants are often of keen interest to these females.

A male patas monkey (Erythrocebus patas)
Ecological Role

Since one of the primary food sources of patas monkeys is arthropods, their presence in an area likely has an impact on these arthropod populations. Patas monkeys do not eat a large amount of fruit or seeds and therefore their role in seed dispersal is likely to be minimal.

Conservation Status and Threats

Overall, the International Union for Conservation of Nature classifies patas monkeys as Near Threatened (IUCN, 2020), appearing on the IUCN’s Red List of Threatened Species. Of the subspecies, the eastern patas monkey is listed as Vulnerable (IUCN, 2017) and the western patas monkeys is Near Threatened (IUCN, 2018). There is no information available about the conservation status of the Aïr patas monkey subspecies.

Of the other two patas monkey species, the southern patas monkey (Erythrocebus baumstarki) is classified as Critically Endangered (IUCN, 2020), with 40–100 mature individuals remaining in the wild, and Heuglin’s patas monkey (Erythrocebus poliophaeus) is classified as Data Deficient (IUCN, 2019), meaning that too little is known about its distribution and population to make an accurate estimate.

All patas monkey populations are decreasing due to habitat loss and fragmentation because of expanding human development. Conversion of savannah woodland to agricultural land threatens this species, as well as deforestation for charcoal production. Patas monkeys are also hunted for their meat and their crop feeding can lead to persecution by farmers. Natural predators include baboons, lions, cheetah, and hyenas.

​Conservation Efforts

Patas monkeys are listed under the Convention on International Trade in Endangered Species (CITES) Appendix II and as Class B under the African Convention. There are a number of protected areas throughout their range, although many populations exist outside of protected areas. Further research is needed on their population trends, as well as further efforts to prevent their populations decreasing further.

References:
  • de Jong, Y. A., Butynski, T. M., & Nekaris, K. A. I. (2008). Distribution and conservation of the patas monkey Erythrocebus patas in Kenya. Journal of East African Natural History, 97(1), 83-102.
  • Enstam, K. L., Isbell, L. A., & De Maar, T. W. (2002). Male demography, female mating behavior, and infanticide in wild patas monkeys (Erythrocebus patas). International Journal of Primatology, 23(1), 85-104.
  • Hall, K. R. L., Boelkins, R. C., & Goswell, M. J. (1965). Behaviour of patas monkeys, Erythrocebus patas, in captivity, with notes on the natural habitat. Folia primatologica, 3(1), 22-49.
  • Isbell, L. A. (1998). Diet for a small primate: insectivory and gummivory in the (large) patas monkey (Erythrocebus patas pyrrhonotus). American Journal of Primatology, 45(4), 381-398.
  • Isbell, L. A., Pruetz, J. D., & Young, T. P. (1998). Movements of vervets (Cercopithecus aethiops) and patas monkeys (Erythrocebus patas) as estimators of food resource size, density, and distribution. Behavioral Ecology and Sociobiology, 42(2), 123-133.
  • Muroyama, Y. (1994). Exchange of grooming for allomothering in female patas monkeys. Behaviour, 128(1-2), 103-119.
  • Nakagawa, N. (2003). Difference in food selection between patas monkeys (Erythrocebus patas) and tantalus monkeys (Cercopithecus aethiops tantalus) in Kala Maloue National Park, Cameroon, in relation to nutrient content. Primates, 44(1), 3-11.
  • https://www.iucnredlist.org/species/174391079

Written by Jennifer Botting, PhD, February 2021