Macaca radiata
bonnet macaque

Bonnet macaques are found in a variety of habitats, including evergreen high forest and dry deciduous forest of the Western Ghat Mountains. They are highly arboreal and are strong swimmers. They often wander onto dry prairies, although it is not their preferred habitat. Bonnet macaques coexist with several primate species, including Nilgiri langurs (or hooded leaf monkeys Trachypithecus johnii), lion-tailed macaques (Macaca silenus), and Hanuman langurs (Semnopithecus entellus). (Dewar, Goldstein, and Richard, 1989; Johnson, Hill, and Cooper, 2007; Sugiyama, 1971)

Bonnet macaques live as commensals with humans and are most abundant on the outskirts of human settlements. In those areas they rely on trash and food generated by villagers and visitors. They are often found sleeping and eating in large Ficus trees which line roads near human settlements. (Dewar, Goldstein, and Richard, 1989; Johnson, Hill, and Cooper, 2007; Sugiyama, 1971)

There are two distinct subspecies recognized: dark-bellied bonnet macaques (Macaca radiata radiata) and pale-bellied bonnet macaques (Macaca radiata diluta). As their common name suggests, bonnet macaques have a whirl of hair radiating from the center of the head. They are grayish brown or golden brown in color. They have hairless faces, which appear pink in the females. (Dunbar and Badam, 2000; Fleagle, 1999; Johnson, Hill, and Cooper, 2007; Sugiyama, 1971)

Captive lifespan in bonnet macaques is up to 35 years. However, few individuals in wild populations make it to this advanced age. Most females in wild populations do not reach the age of menopause, around 27 years old. Lifespan is usually cut short due to predation, car collisions, or disease. (RAO et al., 1998)

Bonnet macaques are arboreal and terrestrial quadrupeds, although they spend much of their time on the ground. They are typically active during the day. Bonnet macaques use lateral-sequence footfall patterns which allows three or more limbs to remain in contact with a branch and reduces lateral swaying. Juvenile bonnet macaques use their 50 to 70 cm prehensile tail as an anchor when going down steeply inclined branches or for grasping support.

Bonnet macaques live in multimale-multifemale troops averaging 30 individuals. Females are philopatric (remain in natal group) and form kin-bonded subgroups. Males transfer to other troops without a period of solitary life. Female dispersal has also been documented, but seems to be rare. There is a linear ranking order among males and females.

Social grooming is a common behavior in bonnet macaques. Unlike many other primate species, grooming is not a one-way social behavior performed by subordinate individuals on dominant individuals. In bonnet macaques dominant males often spend more time grooming others than do juvenile males. All community members participate in social grooming, which is believed to calm tensions and increase bonding.

During rest or sleep, groups of same-sex bonnet macaques huddle together. Dominant males will clasp juvenile males close to them while adult female mothers will huddle together and leave juveniles, single adult females, and babies to huddle together.

Wrestling and mock attacks are commonly observed in juvenile bonnet macaques. Bonnet macaques are unique in that adult males of all ages regularly join in play. Juveniles and infants repeatedly leap at, kick, cling to, and bite big males, without fear of retribution.

Male-male mounting is a common social behavior, the majority of mounting is a dominant male mounting a juvenile. But one third of all observed male-male mounting was a juvenile male mounting a dominant male. (Campbell et al., 2007; Johnson, Hill, and Cooper, 2007; Lindberg, 1980; Silk, 1994; Sugiyama, 1971)

Home Range

Bonnet macaque troops maintain a home range which varies in size, averaging 50 ha for the core area. Daily use patterns are dependent on food distribution and the distribution of predators. They may stay in the same general area for several months before exploring a new area. Langur species, lion-tailed macaques, and other bonnet macaque troops have overlapping home ranges and mix without aggression. (Sugiyama, 1971)

Bonnet macaques use their sensitive hands to gather tactile information on their environment and to participate in grooming. Like many other primates, they have keen vision and can see in color. Vision is relied on heavily to find food, navigate the landscape, and communicate to conspecifics. They have slightly reduced olfaction with narrow, downward facing nostrils. Bonnet macaques use taste to distinguish when fruit is ripe. Alarm calls are an important form of communication. This is a loud vocalization that is emitted in response to detection of a predator.

"Grinning and clicking" is used to express affection and relieve tension. It is characterized by a wide grin with repeated clicking of the tongue. Dominant and subordinate individuals use this form of communication.

"Embracing" occurs when two large males meet. They embrace each other, grip each other’s genitals, and display grinning and clicking behavior. Social tension may be relieved in this greeting behavior.

Females do not advertise sexual receptivity, as they have no sexual swellings. Older, dominant males consort and mate with the same female for several days. Younger males spend less time consorting and mate with several females over the same time span.

Social rank is communicated mostly through maturity, which can be difficult to observe. Some studies have resorted to inducing intra-group aggression through artificial feeding to determine dominance relationships. Results demonstrate that dominance is linear in both males and females. (Ramakrishnan and Coss, 2000; Sugiyama, 1971)

Bonnet macaque populations often rely on food generated by living near human populations. They often inhabit temples where tourists feed them or they take food offerings left at the feet of religious figures. They also raid nearby houses, tourist buses, food stalls, backyard gardens, and large trash piles for food. Populations that do not live near human settlements eat fruits, foliage, insects, and occasional bird eggs or lizards. One account found that a population mainly ate berries, flowers, and young leaves of Lantana, which blooms year-round. Though fruit and young leaves of pongam, fig, karwanda, acacia, tamarind, and nihm were main food items as well. Their favorite food was reported to be grasshoppers (Sugiyama, 1971). Johnson, Hill and Cooper (2007) found that 9 categories made up their diet: vegetation, fruit, human food, soil, seeds, wood, insect, non-food items, and unidentified items. Temple macaque populations ate more vegetation, human food, soil, wood, non-food and unknown items. Forest populations ate more fruit, insects and seeds. (Johnson, Hill, and Cooper, 2007; Sugiyama, 1971)

Bonnet macaques emit high-pitched alarm calls when predators are sighted. They live in groups, which increases the level of vigilance for predators. The alarm call is produced by all members of the group and sounds like “kern kern”. Once an alarm is sounded the community rushes to the shelter of the tree canopy or a bush. In general, the dominant male is the first to come down. Other members paired in twos or threes follow him. Additional data suggests that bonnet macaques are able to recognize and respond to alarm calls of other primate species in the area. They seem to learn the alarm calls of Nilgiri langurs (also called hooded leaf monkeys, Trachypithecus johnii), Hanuman langurs (Semnopithecus entellus), and lion-tailed macaques (Macaca silena) if they are exposed to them frequently enough. Juveniles begin to respond to these alarm calls and the ability to detect them seems to improve with age and experience. Bonnet macaques respond most strongly to alarm calls from their own troop. (Ramakrishnan and Coss, 2000; Sugiyama, 1971)

Bonnet macaques are preyed on by leopards, tigers, eagles, crocodiles, dholes, feral dogs, and large snakes. They are also killed by humans. (Ramakrishnan and Coss, 2000)

Bonnet macaques often live sympatrically with Nilgiri langurs (Tachypithecus johnii) and Hanuman langurs (Semnopithecus entellus). There is limited competition between these species because of dietary differences. Langurs eat more leaves while bonnet macaques are more omnivorous. Populations that live in forests may help in the dispersal of trees through their frugivory. (Ramakrishnan and Coss, 2000; Sugiyama, 1971)

Bonnet macaques and other macaque species are sometimes considered pests where they live near human. They can be aggressive and destructive in their efforts to steal food. They also raid crops. (Dewar, Goldstein, and Richard, 1989; Sugiyama, 1971)

Villagers will often sell fruit or rice to tourists specifically to feed macaques at tourist attractions.

The IUCN Red List of Threatened Species lists bonnet macaques as lower risk/least concern.