PATAS MONKEY FACTS
| Family: Cercopithecidae |
Subfamily: Cercopithecinae |
| Genus: Erythrocebus |
Species:patas |
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There are 4 subspecies.
First named Simia patasby Schreber in 1775.
Appearance:
Large, tall, and slender. Head and body length is around 19.3 in. for females, and between 23.6-34.4in. for males. Adult females weigh between 8.8-15.4lbs; males between 15.4-28.7lbs. They are sexually dimorphic - females are half the size of males. The body fur is reddish gray, paler underneath, matching the tall grass where they live. The face color varies from black to light grey, and they have a mustache and whiskers, usually white. Males have a bright blue scrotum. Infants are uniformally dark brown or grey, with a color change beginning at around three months of age. The whiskers and their erect posture have given rise to their nicknames "Hussar or Sergeant-Major monkey." They are also called the "dancing monkey" because they raise all four feet off the ground to express pleasure or excitement.
Range and Diet:
Called the "most terrestrial of all primates," the patas are said, by one source, to only climb trees when alarmed (SFZoo 1997:2). Another source says they spend "a significant part of their time during daylight hours" feeding in trees (Cords 1987:99). Occurs widely in savannas and woodland fringes, from West Africa to Ethiopia, Kenya, and Tanzania (MSW, 1997). They can exist in semi-arid conditions, and are often found far from water. Their habitat is highly seasonal and unpredictable, mainly due to the availability of water. Their home ranges are larger, and their daily paths and longer and more variable than that of closely related Cercopithecus species. The home ranges of two observed groups varied, with 3,200ha. for the Kenyan group and 5,200ha. for an Ugandan group. Group ranges will often overlap. During dry seasons different groups have been known to share the same water hole. Patas monkeys are not territorial -- they will not defend a territory -- which is said to be unusual among single-male groups (Jolly 1985). However, there are sometimes boundary disputes between females.
Patas monkeys are omnivorous, but the bulk of their diet is Acacia tree parts. They also eat a lot of fruit, and will eat grubs and other ground insects, small reptiles, and perhaps young birds and eggs. They have been observed eating prickly pear cactus. Patas forage in a "highly dispersed manner" (Jolly 1985:254). They prefer solitary feeding - the presence of others trying to feed at the same location in provisioned animals increased the incidents of aggression.
Behavior and Social Structure:
They are normally said to be quiet monkeys. Females and young have a "restrained vocabulary" of hoots, chirrups, low whistles, and a repeated guttural cough (SFZoo 1997:2). Males can make a burring alarm note or bark. All will yawn when annoyed. However, during conflicts they can scream and roar (Struhsaker. 1970).
Patas are terrestrial quadrupeds. They walk on their fingers (digitigrade), not on their palms (palmigrade.) They are the fastest of all primates, they can run at speeds up to 35 miles per hour. It is said that, at a distance, a running patas monkey can be mistaken for a cheetah.
Normally they live in single male, harem groups, though groups with more than one male, and even all-male groups, have been seen (Struhsaker, 1970). Also, some researchers believe their social system may be in transition (see Reproduction and Lifespan below.) Average group size, which was reported by more than one researcher, is around 20, and groups are normally stable in size and composition (Struhsaker, 1970). Described as a "female-bonded" group which means that at least two breeding females, who are often related, will travel and forage in the same group, sharing resources and driving out intruders from rival groups, associate closely, groom each other, and support each other in intratroop disputes. According the Jolly (1985), such alliances occur in the presence of patchy food sources, like fruit trees. Females seem to be the group leaders.
Patas monkeys do not display the obvious dominance hierarchy seen in many other primate species. This has led many researchers to conclude that hiercharchy is unimportant to them. However, York and Rowell (1988) argue that patas lack a "consistent obvious submissive gesture" like the kind seen in macaques and chimpanzees ( 508). They believe that, though their hierarchy is not as rigid or consistent as that of other groups, it still exists. Kaplan and Zucker (1980) found a linear dominance hierarchy among the group they studied, which remained stable during nine months of observation. The females initiated and received most social interactions, while the male remained aloof. They further believed that patas monkeys were more reliant on space as a social buffer, using physical avoidance to show submission rather than the normal repetoire of submissive gestures seen in other groups. However, unlike other primate groups, dominance did not seem to influence social aspects like the amount of grooming received. In fact, they noted the existence of "grooming cliques" where lower-ranking animals actually received more grooming. They concluded that, although there was a dominance hierarchy, "it did not seem important in either the establishment of affiliative bonds as measured by grooming or in controlling and channeling competition for scarce resources" (209). Kaplan and Zucker (1980) also found that genealogy, another factor which often influences primate relationships, played less of a role in patas monkeys in influencing who groomed who, or who supported who in conflicts. However, they felt that more data was needed on this.
Population densities become larger during the peak of the dry season, when groups will gather at the scarce water holes. Up to 100 patas monkeys were seen spending considerable time around a water hole in one field study location (Struhsaker, 1970). Though conflict does increase considerably compared to the rest of the year, they are still said to exhibit surprising tolerance for each other (Jolly, 1985) and also for the baboon troops or vervets that may share their water hole. They seldom meet with any other primate species because of their habitat preference. They get along most peacefully with the vervets, sharing space, but female and juvenile patas monkeys are often supplanted by the baboons. Adult patas males will only give way to adult male baboons, and, even then, not all the time.
Researchers differ on the aggression level they assign to patas (York and Rowell, 1988). However, during conflict, physical aggression between patas monkeys seems to be rare, occurring mainly between juveniles (Zucker, 1994). They will occasionally slap each other, but mostly they give threats in the form of posture, facial gestures, and vocalizations. Adult males will display by bouncing, running about, and shaking branches. Females and juveniles are more often involved in intergroup conflict than are adult males. Females will fight more often over food, especially in provisioned groups having to share space.
Patas were thought to not display the reconciliatory behavior seen in other OW primate species. However, a study of a captive troop showed that, though they lack the special conciliatory gestures seen in chimps and macaques, like embracing and lip smacking, female patas do show increased social behavior both with their former opponent and with their kin, including grooming, and seek to reconcile most often with kin than with non-kin (York and Rowell, 1988).
Reproduction and Lifespan:
All aspects of patas reproduction and development are rigidly timed to fall in with the highly seasonal savanna environment. Mating, birth, and weaning take place at the optimum times. They have the most distinct birth season of any Cercopithecus group, a brief annual mating season which lasts less than two months, usually during the wet season from June to August, though this varies with location (Rowell and Hartwell, 1978). Development is rapid. Females are said to have no true 'estrus cycle,' that is it does not occur with true, biological regularity, but rather seems to be induced in some way. Rowell and Hartwell (1978) identified several factors which may serve to keep female patas monkeys reproductively synchronized, including hormonal and social cues, and changes in the environment, like seasonal changes, or some social change, like the arrival or departure of other patas monkeys. Female patas monkeys show no visible changes during their menstrual cycle and ovulation, no obvious swelling. They also have been seen exhibiting sexual receptivity when they were obvious not fertile, like after they were already pregnant, or during lactation (Harding and Olson, 1986). So, basically, patas females seem like humans in that they lack any good visual or behavioral cues as to when they are ovualating. Loy (1981), based on his study of captives patas, believes that increased group stability brings about more hormonal dependent and less socially-induced etrus, which results in better synchronization of mating behavior with actual ovulation.
Males display a bouncing behavior before mating, which begins to be seen in males as young as 5-6 months. Most sexual interactions are initiated by females. They exhibit more female-to-male grooming during etrus, and tend to stay closer to males. Female rank does not seem to influence their chances of copulating (Loy 1981). The most interesting aspect of their reproductive behavior is seen on the effect it has on their social system. Normally, a one-male/multi-female group, this often changes at mating season. Usually the changes will begin with a takeover of the harem by a new male. However, with him, or immediately after him, come several more males, which mate with the females. So, in effect, the troop becomes multi-male for the duration of the mating season. During this time the group will exhibit behaviors often seen in true multi-male systems, females will invite one or several individuals to mate, and some males will establish consortships with females (Harding and Olson, 1986). Male aggression, including physical aggression, increases at this time, and a "transitive ranking," based on success in agonistic encounters, is formed. However, this ranking does not seem to impress the females overly much, who will continue to mate with whom they choose, including those from the lower ranks. Harding and Olsen's (1986) study of Kenyan patas monkeys showed the most successful in battle was the least successful in copulation. DNA studies have shown that a harem-owners reproductive success decreases with his 'tenure.' After the first year, around half the infants born to his troop were not his own (Ohsawa, Inoue, and Takenaka, 1993). Recent researchers believe that the patas monkey social system may be in the process of changing to multi-male. This is suggested to be a consequence of their having left the forest, where most primate species are single-male groups, for the savanna.
Pregnancy generally lasts 167 days. The birth season coincides with the dry season (Struhsaker, 1970). Give birth by day to minimize predation during the night. Chism, Olson, and Rowell (1983) studied birth among wild patas and concluded the pattern was adaptive. According to them, "group composition and habitat combine to make this species particularly vulnerable to predation at night. In response, patas have evolved a night-resting strategy which uses unpredictability, dispersal, and concealment to lessen the vulnerability to nocturnal predation" (168). Unlike the other savanna-dwelling primate species, the baboons, who rely on multi-males for group defense, the patas troop normally only has a single male. Patas groups never spend two nights in the same place, even if they are in close proximity to the last used area at the end of the next day. Each individual, with the exception of nursing mothers, will sleep in their own tree, and even juveniles will threaten another patas who attempts to share it. They will sleep in the most inaccessible trees they can find, with branches higher up, and will stay in the smallest branches that will hold their weight, or the most concealed area of the tree. Nocturnal births are clearly incompatible with this hiding strategy. Further, female patas tend to give birth at specific times of the day, those times when the rate of group movements are less and the threat of predation is relatively lower. Even females in the last stages of labor will strive to keep up with their group. The patas monkeys tend to vary both their day ranging patterns and their sleeping places, so a monkey who totally loses sight of her group might not ever find them again. The carefully synchronized reproductive patterns of patas females also serve to make group moment slower at that time of year, since so many members are either heavily pregnant or have recently given birth.
Females are highly protective of the young in general, though specific mother-infant relations don't seem to always last very long. There is a high level of allomothering, which may be related to their highly dispersed foraging patterns, where it may be adaptive to display concern for any nearby infant in the event of danger (Jolly 1985). However, in patas monkeys this concern for other infants amounts to wide-spread 'baby-snatching' by the females. Mothers of very young infants must go and retrieve them, which is often difficult to do. Most 'kidnappers' treat the infants well, although the less-experienced of them can be inept. More mature infants tend to free themselves from the intruders, but they don't always go immediately back to their mothers. Most infants tend to form strong bonds with one or more allomothers, especially if their own mothers are reluctant to fight on their behalf. These infants appear to benefit from extra care and attention. They will often be rescued by the allomothers from potentially dangerous situations. The mothers also benefit since, if they are attacked while carrying the infant, the allomother will intercede on the infant's behalf (Chism, 1986). There is significantly more allomothering of female infants than of males.
Infants are precocious, able to climb onto and cling ventrally to their mother by the time they are two days old, some reports suggest sooner. They can move independently from their mothers at around 5 weeks. Bipedal scanning behavior started at 3 months. The first social behavior is play, which starts at about 8 weeks, mounting behavior appears soon after. By the 12th week most mothers will begin to discourage nursing, although they are gentle about it, and a patas with no younger siblings will often get to nurse intermittently for up to 2 years. However, mother-infant closeness steadily decreases over the first 3 months of life, so that by 4-5 months most infants have almost complete locomoter independence and are rarely seen to nurse during the day. This age usually corresponds to the rainy season when food can be easily obtained and eaten by infants. Development is so rapid that very young patas monkeys, of about 7-9 months of age, have been known to survive on their own after being orphaned. Rapid independence is necessary in their habitat. In one study 24% of patas infants were orphaned in one year, and all survived. By one year of age patas monkeys are functionally independent members of their group.
Patas have one of the fastest rates of sexual maturation of all OW monkeys. At about nine months, male infants will begin to harass the adult male. Males will leave their group at puberty, though not all of them get their own harem. Many wind up solitary or in all-male groups. The increased aggression seen at crowded water holes during dry seasons is largely due to attempts by unattached males to take over a harem.
Conservation Status:
Lower Risk - CITES II Listed in CITES - Appendix II, which means "species liable to extinction if trade is not controlled" (Jolly 1985:26) (Primate Gallery Archive, 1997). The 1996 IUCN Red List has it at lower risk/of least concern. They seem to do well in zoos. There is also a free-ranging patas preserve in Sierra Bermeja in SW Puerto Rico, the only free-ranging population outside of Africa, which contains 150 individuals. The climate and vegetation there is said to be similar to that of their African habitat (Gonzalez-Martinez, 1997)
Chism, Olson, and Rowell (1983) identified 12 mammal species as possible predators: 5 felids -- the lion, leopard, cheetah, serval, and caracal; 5 canids -- 3 types of jackal, the wild dog, and the domestic dog; and 2 hyaenid species. During dry seasons they are forced to share water holes with many of these mammals. In addition to these, there are also at least four species of large raptorial birds -- eagles and owls -- which could potentially prey on patas, though none were observed to do so during their study.
Different species pose different threats, depending on the individual patas. For example, jackals prey mainly on young patas. Females, especially those with infants, display more fear of them than adult males. They will also react differently to different predators. They will run quickly from dogs, but will vocalize and move toward some felids, as if to advertise their positon and keep them in sight. They have more than one predator alarm call, and the calls differ for males and females.
In contrast to most large, fierce terrestrial monkeys, patas monkeys prefer to run away and hide than to fight. Kaplan and Zucker (1980) feel that this "strategy of avoidance and concealment" has influenced their foraging patterns and way the monkeys deal with each other socially (212). They will bipedally scan an area when worried to locate other group members. Males will generally lead the group movement, increasing the chances that they will meet predators first, sometimes climbing trees to survey the area before the females approach, and will often act as decoys to let their family escape. They are highly vigilant. They are said to have a "stylized distraction display" (Jolly 1985:254), to divert attention to themselves. Females will run for cover, scooping up any infants in their path, whether or not it's their own, as they go.
Though they prefer retreat, they can be aggressive when their young are threatened. Male patas will attack a jackal after it attacks a juvenile, and three male patas were observed to run down a jackal to save an infant it had snatched (Struhsaker, 1970). They continued to chase the jackal off even after the infant was dropped and retrieved by a female patas. An interesting element in this encounter was that at least two of the males did not belong to the same group as the infant that was attacked, yet still participated in its defense and rescue. Patas monkeys have also been observed to drop stones or branches in defense (Jolly 1985).
Other problems include their relatively less-hospitable habitat -- they are especially vulnerable to droughts. Also, humans hunt them, for various reasons.
Interesting Patas Facts:
Patas monkeys are the only species in their genus, and, as such, unique. Some sources say that, if current conditions do not change, this species may be endangered in the future.
It has been suggested that life on the savanna was one factor responsible for the development of human intelligence. Many researchers interested in the development of early hominids have studied savanna baboons as a model. One theorist asserts that savanna baboons are especially intelligent, relative to other monkeys, and expects we shall find similar abilities in patas monkeys, who also live in the same savanna environment. An in depth study of patas monkeys might prove interesting for this reason.
Patas monkeys are an interesting example of adaptation to their environment. Their social organization, foraging patterns, reproductive patterns, and defense strategies all seem to combine in a remarkably coordinated fashion, with those less-than optimal aspects, like the presence of only one defending male in a predator-filled environment, in the process of change. In spite of this, there seems to be little recent information on this group, judging from the lack of sources on the internet, and cognitive studies seem to be lacking. It would seem that much more research needs to be done.
Current Research with Patas:
(Note: The following are examples of recent research done with these primates, it is by no means an exhaustive list. This list will be periodically updated as more information becomes available. Also, though Mindy's Memory Primate Sanctuary DOES NOT support invasive medical research on primates, some articles of this type will be listed - both for information and as examples of the work that is currently being done with these animals.)
Chism, J; Rogers, W
Male competition, mating success and female choice in a seasonally breeding primate (Erythrocebus patas). ETHOLOGY 103(2): 109-126, 1997.
Isbell LA
Diet for a small primate: Insectivory and gummivory in the (large) patas monkey (Erythrocebus patas pyrrhonotus). AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 45(4): 381-398, 1998.
Strange, D
1997 NORTH AMERICAN REGIONAL STUDBOOK PATAS MONKEY ERYTHROCEBUS PATAS. Houston, Houston Zool Gardens, 1997, 114 pp. (Data through 12/31/96)
References:
Chism J (1986) Development and mother-infant relations among captive patas monkeys. International Journal of Primatology 7(1):49-81.
Chism J Decoding patas social organization. Pp. 86-92 in THE NONHUMAN PRIMATES. Dolhinow P, ed. Mountain View, Mayfield Publ, 1999.
Chism J, Olson DK, and Rowell TE (1983) Diurnal births and perinatal behavior among wild patas monkeys: Evidence of an adaptive pattern. International Journal of Primatology. 4(2): 167-184.
Cords M (1987) Forest guenons and patas monkeys: Male-male competition in one-male groups. In Smuts BS, Seyfarth RM, Wrangham RW, and Struhsaker TT (eds.) Primate Societies. Chicago: The University of Chicago Press. pp. 98-111.
Gonzalez-Martinez J
1997, March 30. Sierra Bermeja Field Study Site.
Available: http://ourworld.compuserve.com/homepages/oceanpkvetclin/sierrabe.htm
Email: [email protected]
Harding RSO and Olson DK (1986) Patterns of mating among male patas monkeys (Erythrocebus patas) in Kenya. American Journal of Primatology 11: 343-358.
Isbell LA (1998) Diet for a small primate: Insectivory and gummivory in the (large) patas monkey (Erythrocebus patas pyrrhonotus). AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 45(4): 381-398.
Isbell LA; Pruetz JD; Lewis M; Young TP (1998) Locomotor activity differences between sympatric patas monkeys (Erythrocebus patas) and vervet monkeys (Cercopithecus aethiops): Implications for the evolution of long hindlimb length in Homo. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 105(2): 199-207.
Jolly A (1985) The Evolution of Primate Behavior. New York: Macmillan Publishing Company.
Kaplan JR and Zucker E (1980) Social organization in a group of free-ranging patas monkeys. Folia Primatologica 34:196-213.
Loy J (1981) The reproductive and heterosexual behaviours of adult patas monkeys in captivity. Animal Behavior 29: 714-726.
MSW (Mammal Species of the World)
1997, March 30. MSW Scientific Names.
Available: http://www.nmnh.si.edu/cgi-bin/wdb/msw/names/query/11165
Email: [email protected]
Ohsawa H, Inoue M, and Yakenaka O (1993) Mating strategy and reproductive success of male patas monkeys (Erythrocebus patas). Primates 34(4):533-544.
Primate Gallery Archive
1997, March 30. Subfamily Cercopithecinae - Erythrocebus
Available: http://www.selu.com/~bio/PrimateGallery/primates/Erythrocebus.html
Primate Information Center. , Manager. . Washington Regional Primate Research Center and the Health Sciences Libraries. University of Washington, Seattle
Rowe N (1996) The Pictorial Guide to the Living Primates. East Hampton: Pogonias Press
Rowell TE and Hartwell KM (1978) The interaction of behavior and reproductive cycles in patas monkeys. Behavioral Biology 24:141-167.
SFZoo
1997, March 30. Primate Discovery Center.
Available: http://www.sfzoo.com/html/map.primateDC.html
Struhsaker TT and Gartlan JS (1970) Observations on the behaviour and ecology of the patas monkey (Erythrocebus patas) in the Waza Reserve, Cameroon. Journal of Zoology, London. 161:49-63.
York AD and Rowell TE (1988) Reconciliation following aggression in patas monkeys, Erythrocebus patas. Animal Behavior 36:502-509.
Zucker EL (1994) Severity of agonism of free-ranging patas monkeys differs according to the composition of dyads. Aggressive Behavior 20: 315-323.
