Macaca sinica
toque macaque

Macaca sinica is endemic only to the island of Sri Lanka. It is found in all areas of this country excluding the Jaffina Peninsula in northern Sri Lanka and is also not found in the Trincomalee area in northeastern Sri Lanka. (Fooden, 1979)

Toque macaques live in a variety of biomes throughout Sri Lanka. They spend a large amount of time in trees and live in all types of forests. The type of trees and tree height varies with region. The most important resource is a source of drinking water. This accounts for the lack of any M. sinica in the northern penninsula and parts of southern Sri Lanka. As a result of occupying separate regions two sub species are recognized. The lowland species, Macaca sinica sinica, lives in northern Sri Lanka. This region has much smaller trees and only receives one meter of rainfall a year. The highland species, Macaca sinica aurifrons, lives in the evergreen forests of southwestern Sri Lanka. This region gets over three meters of rainfall a year. (Fooden, 1979)

Toque macaques are the smallest species of Macaca. They have a golden brown coat on their dorsal surface and white hair on their ventral surface. This white coat extends to the cheeks and around the ears. The have a small tuft of hair on the top of their head that resembles a hat. The amount of hair on the top of the head is geographically variable within their range. They have a long tail that is black dorsally and pale white ventrally. Toque macaques have muscular cheek pouches that are used for storage during foraging. These pockets are lined with mucous and the muscles serve to push the food back into their mouth. Individuals have thirty two teeth; their dental formula is 2/2, 1/1, 2/2, 3/3. There is sexual dimorphism in canine size, with males having larger canines. All of their molars are quadrucuspid. Their faces are hairless. Toque macaque males have a tan face while females have different shades of pink. Males are larger than females and complete their development later. Females have a head and body length of 400 mm while males are around 475 mm. Both males and females have long tails that are slightly longer than their head and body length. Their ears and lips are black. Toque macaques may be the smallest species of Macaca, but they have one of the largest tails compared to body size. They also have very large ears that are 9% of the head and body length. Their basal metabolic requirement is 150 kcal/kg daily. There are two described subspecies of M. sinica: Macaca sinica aurifrons, which lives in the lowland dry region in northern Sri Lanka, and Macaca sinica sinica, which lives in the wet evergreen forests in southern Sri Lanka. Macaca sinica sinica is slightly larger has darker, denser, dorsal hair. (Fooden, 1979; Harris, 1970; Napier, 1967)

The lifespan of toque macaques in the wild is about the same as in captivity, up to 35 years. The expected lifespan in the wild is low due to high infant mortality rates. There is also significant mortality among adolescent males when they venture off to join a different troop. Once toque macaques have reached sexual maturity they will likely live to an old age. (Fooden, 1979; Michael and Crook, 1973)

Toque macaques are mainly arboreal, spending much of their time in trees. In trees they use a quadripedal style of locomotion. When walking on the ground, they walk on their digits. Bipedal walking occurs on the ground when the hands are full. They are social, forming groups of up to forty members. These groups are long-standing, but emigration between groups occurs in males during the late juvenile stage. In groups there is a 2 to 1 ratio of females to males. Toque macaques are very active and forage for food for a large part of every day. Males and females play different roles in groups. Males lead the group and settle fights between younger members. They play no role in the raising of young. Females are the primary care providers for young and a female's position in the dominance hierarchy may influence that of her young. The age distribution is even, with half of group members being adults and half infants or juveniles. There is a clear dominance hierarchy in groups, with the oldest male being most dominant. Following the oldest males are subadult males, adult females, and finally juveniles. (Dittus and Ratnayeke, 1989; Fooden, 1979; Napier, 1967)

Home Range

Home range sizes of toque macaques are not reported, although groups defend areas against other social groups. (Fooden, 1979)

Toque macaques are diurnal primates that rely heavily on vision. They have excellent stereoscopic and color vision. Often they distinguish between food sources using their vision, instead of smell. As in other primates, Toque macaques have excellent control over their hands and feet. They have well developed thumb-index finger control. They use acoustic communication among individuals and groups. There has been 30 different vocalizations recorded. They use warning calls to alarm other group members of danger and other vocal communication during play. There is a clear dominance hierarchy in groups of M. sinica and the dominant male is easy to identify. He is generally well groomed and muscular. Grooming is a common social activity. During the breeding season females communicate that they are in estrous by secreting a pungent mucous from their cervix that males smell. (Eimerl and DeVore, 1965; Fooden, 1979)

Toque macaques spend much of their day foraging for food in trees and on the ground. They have special pouches in their cheeks that are used to store food during foraging. If they sense danger while foraging they will put their food in their mouth and flee to safety. Once safe they will eat the contents. The diet consists mostly of fruit. They also eat tree flowers, buds, and leaves. In their range there are 46 different types of trees, only 6 of which are not utilized for food. When available they will eat small invertebrates or vertebrates such as birds or lizards. Although these are not a main source of energy for M. sinica they represent an important source of protein and a considerable portion of time is spent searching for such prey. During the dry season water obtained from food is not enough to sustain toque macaques, so they must make daily trips to watering holes. Toque macaques also raid crop, such as rice, cocoa, and coconut. (Fooden, 1979; Harris, 1970)

Toque macaques spend most of their time in trees, which limits their exposure to potential predators. When on the ground they appear much more cautious then when they are in the trees. They avoid open spaces when possible. When they must be in the open, they stay in compact groups. When any member senses danger the whole group will flee to nearby trees. When frightened they sometimes freeze in place when in dense foliage. To avoid predation they sleep high in forks of trees that are far from the central trunk. Groups of M. sinica rarely sleep in the same tree over consecutive nights to avoid predation. They do fall prey to large, arboreal predators, including snakes, and possibly to large avian predators, although none are reported. (Fooden, 1979)

Toque macaques play many roles in their ecosystem. It is estimated that a troop will eat up to 1 percent of the annual fruit production of the forest they live in. Through their frugivory they also help to disperse seeds. They are predators of small lizards and birds, but these are not a staple of their diet. Toque macaques a commensal relationship with two species of monkeys, Hanuman langurs (Semnopithecus entellus) and purple-faced langurs (Trachypithecus vetulus), with which they co-occur. They are often observed foraging together. They do not compete for food resources as M. sinica primarily eats fruit and both Presbytis species eat leaves. They are hosts to a variety of parasites. (Dewit et al., 1991; Fooden, 1979)

There is significant persecution of toque macaques as they are considered crop pests. They are shot and poisoned as ways to keep them out of crops. They are also known zoonotic vectors of Trichuris, Ascaris, and certain strongyle worms. ("The IUCN Red List of Threatened Species", 2009; Dewit et al., 1991)

Toque macaques are not economically important in Sri Lanka. They are widely viewed as pests because they raid crops and garbage dumps. They are sometimes sold as pets. ("The IUCN Red List of Threatened Species", 2009)

Toque macaques are listed as endangered according to the IUCN Red List. Their population has been decreasing steadily and total population size has been cut in half over the last 40 years. This loss is due to habitat destruction and persecution of M. sinica by humans. Although they are protected internationally, they are not protected by Sri Lankan law. There are many parks and reserves in Sri Lanka where toque macaques occur. ("The IUCN Red List of Threatened Species", 2009; "U.S. Fish, Wildlife Service Threatened, and Endangered Species System", 1976)