Olive baboon | |
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In the Ngorongoro Conservation Area, Tanzania | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Primates |
Suborder: | Haplorhini |
Infraorder: | Simiiformes |
Family: | Cercopithecidae |
Genus: | Papio |
Species: | P. anubis [2] |
Binomial name | |
Papio anubis [2] (Lesson, 1827) | |
Geographic range |
The olive baboon (Papio anubis), also called the Anubis baboon, is a member of the family Cercopithecidae Old World monkeys. The species is the most wide-ranging of all baboons, [3] being native to 25 countries throughout Africa, extending from Mali eastward to Ethiopia [4] and Tanzania. Isolated populations are also present in some mountainous regions of the Sahara. [3] It inhabits savannahs, steppes, and forests. [3] The common name is derived from its coat colour, which is a shade of green-grey at a distance. A variety of communications, vocal and non-vocal, facilitate a complex social structure.
The olive baboon is named for its coat, which, at a distance, is a shade of green-grey. [5] At closer range, its coat is multicoloured, due to rings of yellow-brown and black on the hairs. [6] The hair on the baboon's face is coarser and ranges from dark grey to black. [5] This coloration is shared by both sexes, although males have a mane of longer hair that tapers down to ordinary length along the back. [3]
Besides the mane, the male olive baboon differs from the female in terms of weight, body and canine tooth size; males are, on average, 70 cm (28 in) tall while standing and females measure 60 cm (24 in) in height. [7] The olive baboon is one of the largest species of monkey; only the chacma baboon and the mandrill attain similar sizes. [8] The head-and-body length can range from 50 to 114 cm (20 to 45 in), with a species average of around 85 cm (33 in). At the shoulder on all fours, females average 55 cm (22 in) against males, which average 70 cm (28 in). The typical weight range for both sexes is reportedly 10–37 kg (22–82 lb), with males averaging 24 kg (53 lb) and females averaging 14.7 kg (32 lb). Some males may weigh as much as 50 kg (110 lb). [9] [10]
Like other baboons, the olive baboon has an elongated, dog-like muzzle. [3] Its 38 to 58 cm (15 to 23 in) long tail and four-legged gait can make it seem canine. [11] The tail almost looks as if it is broken, as it is erect for the first quarter, after which it drops down sharply. [5] The bare patch of a baboon's rump is smaller in the olive baboon than in the Hamadryas baboon or Guinea baboon. [3] The olive baboon, like most cercopithecines, has a cheek pouch with which to store food. [12]
The species inhabits a strip of 25 equatorial African countries, very nearly ranging from the east to west coasts of the continent. [12] The exact boundaries of this strip are not clearly defined, as the species' territory overlaps with that of other baboon species. [5] In many places, this has resulted in cross-breeding between species. [5] For example, considerable hybridisation has occurred between the olive baboon and the hamadryas baboon in Ethiopia. [11] Cross-breeding with the yellow baboon and the Guinea baboon has also been observed. [5] Although this has been noted, the hybrids have not as yet been well studied. [5]
Throughout its wide range, the olive baboon can be found in a number of different habitats. [3] It is usually classified as savannah-dwelling, living in the wide plains of the grasslands. [13] The grasslands, especially those near open woodland, do make up a large part of its habitat, but the baboon also inhabits rainforests and deserts. [3] Uganda and the Democratic Republic of the Congo, for instance, both support olive baboon populations in dense tropical forests. [5]
The olive baboon lives in groups of 15 to 150, made up of a few males, many females, and their young. [14] Each baboon has a social ranking somewhere in the group, depending on its dominance. [14] Female dominance is hereditary, with daughters having nearly the same rank as their mothers, [14] [15] and adult females forming the core of the social system. [15] Female relatives form their own subgroups in the troop. [14] Related females are largely friendly to each other. They tend to stay close together and groom one another, and team up in aggressive encounters within the troop. [15] Female kin form these strong bonds because they do not emigrate from their natal groups. [16]
Occasionally, groups may split up when they become so large that competition for resources is problematic, but even then, members of matrilines tend to stick together. [16] Dominant females procure more food, matings, and supporters. Among olive baboons in Tanzania, high-ranking females give birth at shorter intervals to infants with a higher survival rate, and their daughters tend to mature faster than low-ranking females. [16] These high-ranking females also appear to have a higher probability of miscarriages and some high-ranking matrilines have inexplicably low fertility. [16] One theory suggests this occurs due to stress on the high-ranking females, although this theory is controversial. [16] A recent study shows top-ranking females are at risk from male harassment. Males who have recently immigrated harass females in order to induce miscarriages in females they had not yet mated with, in order to impregnate them with an offspring that is his own faster. As females with living infants often have male allies protecting their infants, it makes more sense for a male to ignore infants and channel his aggression to the group's resident pregnant females who do not currently have infants instead. [17]
A female often forms a long-lasting social relationship with a male in her troop, known as a "friendship". [15] These nonsexual affiliative friendships benefit both the male and female. [16] Males benefit from these relationships because they are usually formed soon after he immigrates into a new group, [16] and helps the male integrate into the group more easily. [16] He could also potentially end up mating with his female friend in the future. [16] Females gain protection from threats to themselves and their infants (if they have any). [16] Males occasionally "baby-sit" for their female friends, so she can feed and forage freely without the burden of having to carry or watch the infant. [16] Sexually receptive females and newly immigrated males can form such friendships. [14] These relationships are sometimes enduring and the pair grooms and remains close to each other. [14] They also travel, forage, sleep, and raise infants together, as well as fight together against aggressive conspecifics. [15]
Females with high social ranks even forge friendships with multiple males at once. Another advantage of these friendships is it enables females to gain protection from the unwanted advances of males aiming to mate with them. A female who finds a male undesirable can simply rebuff his advances by calling on her male friends to chase him away, and can therefore enjoy exerting her reproductive skew. While infanticide is a reproductive strategy in males, it is costly for females, which would also explain why infanticide is a rare occurrence in olive baboons yet can be the principal cause of infant mortality in many other baboon subspecies: high-ranking females can simply rebuff a male threatening her infant, making infant-targeted aggression a reproductive disadvantage in olive baboons. This also explains the reason male olive baboons use infants as shields in aggressive encounters. [18]
Males establish their dominance more forcefully than females. [14] A male disperses, [16] or leaves his natal group and joins another group, after reaching sexual maturity. [14] Adult males are very competitive with each other and fight for access to females. [15] Higher dominance means better access to mating and earlier access to food, so naturally a great deal of fighting over rank occurs, with younger males constantly trying to rise in position. [14] Because females stay with their groups their entire lives, and males emigrate to others, often a new male challenges an older one for dominance. [14] Frequently, when older baboons drop in the social hierarchy, they move to another tribe. [3] The younger males who pushed them down often bully and harass them. [3] Older males tend to have more supportive and equal relationships than those of the younger males. The former may form coalitions against the latter. [19]
Despite being hierarchical, baboons appear to be "democratic" when it comes to deciding the direction of collective movement. Individuals are more likely to follow when multiple decision-makers agree on what direction to go rather than simply following dominant individuals. [20]
Females are sexually mature at seven to eight years old, and males at seven to 10 years. [3] The beginning of a female's ovulation is a signal to the males that she is ready to mate. During ovulation, the skin of the female's anogenital area swells and turns a bright red/pink. [21] The swelling makes it difficult to move and increases the female's chance of microbial or parasitic infection. [21] Females with more swollen anogenital areas reproduce while younger, produce more offspring per year, and those offspring have a better chance of surviving. These females also attract more males, and are more likely to cause aggressive fights between them. [14] Olive baboons tend to mate promiscuously. [14] A male forms a mating consortship with an estrous female, staying close to and copulating with her. [22] Males guard their partner against any other male trying to mate with her. Unless a female is in a multiday consortship, she often copulates with more than one male each day. [23] Multiple copulations are not necessary for reproduction, but may function to make the actual paternity of the female's offspring ambiguous. This lack of paternal certainty could help reduce the occurrence of infanticide. [3] Occasionally, male olive baboons monopolize a female for her entire period of probable conception. [23] The male protects his female from being mated by other males during consortship. [24]
Newborns have black natal coats and bright pink skin. Females are the primary caregivers of infants, but males also play a role. [14] In its first few days, the infant may be unable to stay attached to its mother and relies on her for physical support. Its grasp grows stronger by its first week and it is able to cling to its mother's fur by itself. [14] By two weeks, the infant begins to explore its surroundings for short periods, but stays near her. The distance the infant spends away from its mother increases the older it gets. [25] In general, higher-ranking females are usually more relaxed parents than females of lower rank, which usually keep their offspring close to them. [3] This difference lasts for approximately the first eight weeks of an infant's life. [3] Olive baboons do not seem to practise co-operative parenting, but a female may groom an infant that is not hers. Subadult and juvenile females are more likely to care for another's young, as they have not yet produced offspring of their own. [3] One theory for why immature females tend to seek out infants is that they can prepare for their future roles as mothers. [16] Infant baboons born to first-time mothers suffer higher mortality than those born to experienced mothers, which suggests that prior experience in caring for infants is important. [16] Adult males in the groups also care for the infants, as they are likely to be related to them. [26] Males groom infants, reducing the amount of parasites they may have, and calm them when they are stressed. They may also protect them from predators, such as chimpanzees. Adult males exploit infants and often use them as shields to reduce the likelihood that other males will threaten them. [26]
Olive baboons communicate with various vocalizations and facial expressions. Throughout the day, baboons of all ages emit the "basic grunt". [27] Adults give a range of calls. The "roargrunt" is made by adult males displaying to each other. The "cough-bark", and the "cough geck" are made when low-flying birds or humans they do not know are sighted. A "wa-hoo" call is made in response to predators or neighbouring groups at night and during stressful situations. [27] Other vocalizations include "broken grunting" (low-volume, quick series of grunts made during relatively calm aggressive encounters), "pant-grunts" (made when aggressive encounters escalate), "shrill barks" (loud calls given when potential threats appear suddenly), and "screams" (continuous high-pitch sounds responding to strong emotions). [27] The most common facial expression of the olive baboon is "lipsmacking", which is associated with a number of behaviours. [14] "Ear flattening", "eyes narrowed", "head shaking", "jaw-clapping", lipsmacking, and "tongue protrusion" are used when baboons are greeting each other, and are sometimes made with a "rear present". [27] "Eyebrow raising", "molar grinding", "staring", and "yawning" are used to threaten other baboons. [14] A submissive baboon responds with displays such as the "fear grin", the "rigid crouch", and "tail erect". [27]
One major reason for its widespread success is that the olive baboon is omnivorous and like other baboons, will eat practically anything. [5] As such, it is able to find nutrition in almost any environment and is able to adapt with different foraging tactics. [28] For instance, the olive baboon in grassland goes about finding food differently from one in a forest. [5] The baboon forages on all levels of an environment, above and beneath the ground and in the canopy of forests. [28] Most animals only look for food at one level; an arboreal species such as a lemur does not look for food on the ground. The olive baboon searches as wide an area as it can, and it eats virtually everything it finds. [28]
The diet typically includes a large variety of plants, and invertebrates and small mammals, as well as birds. [29] The olive baboon eats leaves, grass, roots, bark, flowers, fruit, lichens, tubers, seeds, mushrooms, corms, and rhizomes. [29] Corms and rhizomes are especially important in times of drought, because grass loses a great deal of its nutritional value. [29] In dry, arid regions, such as the northeastern deserts, small invertebrates like insects, grubs, worms, spiders, and scorpions fill out its diet. [29]
The olive baboon also actively hunts prey, such as small rodents, birds and other primates. [5] Its limit is usually small antelope, such as Thomson's gazelle, but will also kill sheep, goats, and chickens from farms, which may amount to around one third of its food from hunting. [5] Hunting is usually a group activity, with both males and females participating. [5] This systematic predation was apparently developed recently. [30] In a field study, such behaviour was observed as starting with the males of one troop and spreading through all ages and sexes. [30]
In Eritrea, the olive baboon has formed a symbiotic relationship with that country's endangered elephant population. The baboons use the water holes dug by the elephants, while the elephants use the tree-top baboons as an early warning system. [31]
The olive baboon is listed as least concern on the IUCN Red List because it is widespread with a large global population and not threatened by a range-wide population decline. [1] Competition and disease have possibly led to fewer baboons in closed forests. Like most other baboon species, it is routinely exterminated as a pest for crop raiding and small livestock predation. [32] [33]
The Japanese macaque, also known as the snow monkey, is a terrestrial Old World monkey species that is native to Japan. Colloquially, they are referred to as "snow monkeys" because some live in areas where snow covers the ground for months each year – no other non-human primate lives farther north, nor in a colder climate. Individuals have brownish grey fur, pinkish-red faces, and short tails. Two subspecies are known.
The gelada, sometimes called the bleeding-heart monkey or the gelada baboon, is a species of Old World monkey found only in the Ethiopian Highlands, living at elevations of 1,800–4,400 m (5,900–14,400 ft) above sea level. It is the only living member of the genus Theropithecus, a name derived from the Greek root words for "beast-ape". Like its close relatives in genus Papio, the baboons, it is largely terrestrial, spending much of its time foraging in grasslands, with grasses comprising up to 90% of its diet.
In the zoological field of ethology, a dominance hierarchy is a type of social hierarchy that arises when members of animal social groups interact, creating a ranking system. A dominant higher-ranking individual is sometimes called an alpha, and a submissive lower-ranking individual is called a beta. Different types of interactions can result in dominance depending on the species, including ritualized displays of aggression or direct physical violence. In social living groups, members are likely to compete for access to limited resources and mating opportunities. Rather than fighting each time they meet, individuals of the same sex establish a relative rank, with higher-ranking individuals often gaining more access to resources and mates. Based on repetitive interactions, a social order is created that is subject to change each time a dominant animal is challenged by a subordinate one.
The yellow baboon is a baboon in the family of Old World monkeys. The species epithet means "dog-head" in Greek, due to the dog-like shape of the muzzle and head. Yellow baboons have slim bodies with long arms and legs along with yellowish-brown hair. They resemble the chacma baboon, but are somewhat smaller and with a less elongated muzzle. Their hairless faces are black, framed with white sideburns. Males can grow to about 84 cm, females to about 60 cm. They have long tails which grow to be nearly as long as their bodies. The average life span of the yellow baboon in the wild is roughly 15–20 years; some may live up to 30 years.
The hamadryas baboon is a species of baboon within the Old World monkey family. It is the northernmost of all the baboons, being native to the Horn of Africa and the southwestern region of the Arabian Peninsula. These regions provide habitats with the advantage for this species of fewer natural predators than central or southern Africa where other baboons reside. The hamadryas baboon was a sacred animal to the ancient Egyptians and appears in various roles in ancient Egyptian religion, hence its alternative name of 'sacred baboon'.
The Guinea baboon is a baboon from the Old World monkey family. Some (older) classifications list only two species in the genus Papio, this one and the hamadryas baboon. In those classifications, all other Papio species are considered subspecies of P. papio and the species is called the savanna baboon.
The chacma baboon, also known as the Cape baboon, is, like all other baboons, from the Old World monkey family. It is one of the largest of all monkeys. Located primarily in southern Africa, the chacma baboon has a wide variety of social behaviours, including a dominance hierarchy, collective foraging, adoption of young by females, and friendship pairings. These behaviors form parts of a complex evolutionary ecology. In general, the species is not threatened, but human population pressure has increased contact between humans and baboons. Hunting, trapping, and accidents kill or remove many baboons from the wild, thereby reducing baboon numbers and disrupting their social structure.
Social grooming is a behavior in which social animals, including humans, clean or maintain one another's bodies or appearances. A related term, allogrooming, indicates social grooming between members of the same species. Grooming is a major social activity and a means by which animals who live in close proximity may bond, reinforce social structures and family links, and build companionship. Social grooming is also used as a means of conflict resolution, maternal behavior, and reconciliation in some species. Mutual grooming typically describes the act of grooming between two individuals, often as a part of social grooming, pair bonding, or a precoital activity.
A harem is an animal group consisting of one or two males, a number of females, and their offspring. The dominant male drives off other males and maintains the unity of the group. If present, the second male is subservient to the dominant male. As juvenile males grow, they leave the group and roam as solitary individuals or join bachelor herds. Females in the group may be inter-related. The dominant male mates with the females as they become sexually active and drives off competitors, until he is displaced by another male. In some species, incoming males that achieve dominant status may commit infanticide.
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The Amboseli Baboon Project is a long-term, individual-based research project on yellow baboons in the Amboseli basin of southern Kenya. Founded in 1971, it is one of the longest-running studies of a wild primate in the world. Research at the Amboseli Baboon Project centers on processes at the individual, group, and population levels, and in recent years has also included other aspects of baboon biology, such as genetics, hormones, nutrition, hybridization, parasitology, and relations with other species. The project is affiliated with the Department of Ecology and Evolutionary Biology at Princeton University, the Department of Biology and the Evolutionary Anthropology Department at Duke University, the Department of Biological Sciences at the University of Notre Dame, and the Department of Primate Behavior and Evolution at the Max Planck Institute for Evolutionary Anthropology.
Sexual dimorphism describes the morphological, physiological, and behavioral differences between males and females of the same species. Most primates are sexually dimorphic for different biological characteristics, such as body size, canine tooth size, craniofacial structure, skeletal dimensions, pelage color and markings, and vocalization. However, such sex differences are primarily limited to the anthropoid primates; most of the strepsirrhine primates and tarsiers are monomorphic.
Baboons are primates comprising the genus Papio, one of the 23 genera of Old World monkeys, in the family Cercopithecidae. There are six species of baboon: the hamadryas baboon, the Guinea baboon, the olive baboon, the yellow baboon, the Kinda baboon and the chacma baboon. Each species is native to one of six areas of Africa and the hamadryas baboon is also native to part of the Arabian Peninsula. Baboons are among the largest non-hominoid primates and have existed for at least two million years.
Basic requirements of individual primates include obtaining food, avoiding predators, and reproducing. When these basic requirements are best pursued in the company of others, groups will form. Multi-male groups, also known as multi-male/multi-female, are a type of social organization where the group contains more than one adult male, more than one adult female, and offspring. This structure is characterized by group living, polygynandrous, and strong reproductive competition among males, which could result in an uneven division of male reproductive success. There are no stable heterosexual bonds as both males and females have a number of different mates. Multi-male groups are common among semi-terrestrial primates, like savanna baboons, macques, colobus and some New World monkeys.
One-male groups are a type of social organization where one male interacts with a group of females and their immature offspring. Offspring of both sexes are evicted from the group upon reaching puberty. It can be seen in many species of primates, including the gelada baboon, the patas monkey, savanna baboon, sun-tailed monkey, golden snub-nosed monkey, and the hamadryas baboon. There are costs and benefits for individuals living in one-male groups. As well, individuals within one-male groups can interact with each other just like individuals can interact with those from different one-male groups.
Sexual swelling, sexual skin, or anogenital tumescence refers to localized engorgement of the anus and vulva region of some female primates that vary in size over the course of the menstrual cycle. Thought to be an honest signal of fertility, male primates are attracted to these swellings; preferring, and competing for, females with the largest swellings.
Sexual coercion among animals is the use of violence, threats, harassment, and other tactics to help them forcefully copulate. Such behavior has been compared to sexual assault, including rape, among humans.
In biology, paternal care is parental investment provided by a male to his own offspring. It is a complex social behaviour in vertebrates associated with animal mating systems, life history traits, and ecology. Paternal care may be provided in concert with the mother or, more rarely, by the male alone.
Infanticide in non-human primates occurs when an individual kills its own or another individual's dependent young. Five hypotheses have been proposed to explain infanticide in non-human primates: exploitation, resource competition, parental manipulation, sexual selection, and social pathology.
Primate sociality is an area of primatology that aims to study the interactions between three main elements of a primate social network: the social organisation, the social structure and the mating system. The intersection of these three structures describe the socially complex behaviours and relationships occurring among adult males and females of a particular species. Cohesion and stability of groups are maintained through a confluence of factors, including: kinship, willingness to cooperate, frequency of agonistic behaviour, or varying intensities of dominance structures.
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