The common patas monkey ( Erythrocebus patas), also known as the hussar monkey,
Taxonomy
There is some confusion surrounding if there are valid subspecies, with some listing four, others three,
and others listing two: the western
Erythrocebus patas patas (with a black nose) and the eastern
E. patas pyrrhonotus (with a white nose). However, it was later discovered that the nose colour used to separate these subspecies could change to white during pregnancy in females, as well as in general as animals aged, and
E. patas pyrrhonotus in Kenya often did not have white noses,
[
]
The genus status of the species has previously been in flux. Colin Groves first argued the species was closely related to Cercopithecus aethiops in 1989, based on anatomical morphology. Phylogenetic evidence from 2003 appeared to validate him, finding the patas monkey to form a clade within the vervet genus Cercopithecus together with C. aethiops and C. lhoesti, and based on this study Erythrocebus was proposed to be sunk into synonymy with Cercopithecus.
Erythrocebus was previously thought to be a Monotypic taxon containing only E. patas. However, a 2017 study proposed splitting E. patas into three species ( E. patas Sensu, E. poliphaeus, and E. baumstarki) based on morphological differences and heavy geographic separation between taxa, with the IUCN Red List and American Society of Mammalogists following through with this.
Description
The male common patas monkey grows to to in length, excluding the tail, which measures . Adult males are considerably larger than adult females, which average in length.[Kurt J. Gron (2006), Primate Factsheets: Patas monkey ( Erythrocebus patas) Taxonomy, Morphology, & Ecology. Accessed 23 July 2018.]
Adult males average and adult females , showing a high degree of sexual dimorphism.
Distribution and habitat
Patas monkeys live in dry, open woodland.
Behavior
The common patas monkey lives in multi-female groups of up to 60 individuals (although much larger aggregations have been reported). The group contains just one adult male for most of the year. During the breeding season, outside males come into the group to mate with the females.
Among primates, patas monkeys have the longest daily travel distances and the largest home ranges for their body size.
The common patas monkey feeds on , gum, , and Rhizome, a diet more characteristic of much smaller primates.
Mating
Mating in common patas monkeys is seasonal and occurs for roughly one month each year.[Thelma Rowell (1987). On the significance of the concept of the harem when applied to animals. Social Science Information, 26(3), 649-669. https://doi.org/10.1177/053901887026003010 (Original work published 1987)] A female solicits mating by running past a male with her tail curled up and crouching in front of him. On some occasions, she'll also drool and puff out her cheeks.
Female social organization
Variation in the female social structure of patas monkeys has been observed across different populations. This variation may be dependent on food resources, as conflict between individuals is often a result of competition for limited resources. Higher rates of conflict over dense, but limited, food, such as fruit bushes, is associated with more stable, well defined dominance hierarchies than habitats with more diffuse resources, such as insects. Variation in the availability of these resources has been associated with variation in dominance hierarchies among females.
Conflict among females has also shown the presence of recognition among matrilineal relatives. It has been observed that, shortly after conflicts among two females, patas monkeys often act differently toward each other than if they had not been in conflict. Females often reconcile with each other by activities such as sitting together and grooming. While this reconciliatory behavior is observed even between unrelated individuals, it is most common among matrilineal relatives. Dominance structure has relatively little effect on the probability of reconciliation occurring, except that the alpha-female is the least reconciliatory of the females. Affiliation toward matrilineal relatives is common in other primates as well, such as vervet monkeys.
Cooperation among females has also been observed. Adult females without children may help rear others' infants. In a captive group, a female would regularly take and suckle an infant younger than her own.
Male social organization
Outside of mating season (which is roughly one month a year), relatively stable groups with one adult male and several females are the norm. This leaves an excess of males that either form all-male groups or live on their own. During the mating season, when females become receptive, outside males come into the group to mate with females "in apparently total promiscuity."
Young males have been observed to leave their natal groups anywhere from two to four years of age, with variation between groups. The reason young males leave their natal group remains undetermined. While adult males have been observed to act aggressively toward young males in captivity, wild patas monkeys leave their group without any aggression from the adult male. The juveniles spend less and less time with the adult females in the group but not the adult male. This may indicate weakening of matrilineal ties rather than male aggression as the main reason juveniles disperse from their natal group.
Alarm calls
Common patas monkeys have several distinct alarm calls that warn members in the group of predators. Different alarm calls are given by different group members (i.e. adult females, adult males, juveniles, etc.) and certain alarm calls are distinctive of different types of predators. Unlike other primates, patas monkeys rarely take refuge from predators in trees. This is most likely due to the relatively sparse tree cover in patas monkey habitats. While patas monkeys usually run on the ground away from predators, individuals have been observed to attack predators such as jackals and wildcats. This behavior has been observed in both males and females.
In popular culture
The relationship between the patas monkey and the whistling thorn acacia may have inspired The Lorax by Dr. Seuss.[Joanna Klein, "Can It Be? The Lorax Sprang from a Monkey?: A New Essay Explores the Possible Real-life Inspiration for a Dr. Seuss Character", The New York Times, August 7, 2018, p. D6.]
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