Geographic Distribution and Habitat
Toque macaques are found only in Sri Lanka, an island country of South Asia, located in the Indian Ocean to the southwest of the Bay of Bengal and to the southeast of the Arabian Sea and considered one of the world’s 25 biodiversity hotspots. Locally, these Old World monkeys are referred to as rilewa or rilawa. They are accordingly recognized as three separate subspecies for the three distinct regions in which they are found, occupying a variety of forest types at varying altitudes—depending on the subspecies, up to 6,890 ft (2,100 m), with an average elevation of 3,281 ft (1,000 m).
- Dry-zone toque macaques, also known as common toque macaques (Macaca sinica sinica), live in dry zones of the north and east regions of the island; they inhabit dry evergreen forests near water. This subspecies is often referred to by its nickname, “temple monkey.” The monkeys are often sighted at Sri Lanka’s Cultural Triangle, where many ancient monuments including temples are located.
- Wet-zone toque macaques, also known as pale-fronted or dusky toque macaques (Macaca sinica aurifrons), live in wet zones of the southwestern region of the island; they inhabit lowland and midland tropical rainforests and wet zone lowland forests.
- Highland toque macaque, also known as hill-zone or mountain toque macaques (Macaca sinica opisthomelas), live in the highlands of the central region of the island; they inhabit montane tropical rainforests.
Size, Weight, and Lifespan
The species exhibits sexual dimorphism: males are physically larger than females, and males are fitted with larger canine teeth.
Male toque macaques weigh between 8.8 and 12 lb (4.0–5.5 kg); head-to-body length is about 18.7 in (47.5 cm). Female toque macaques weigh between 5.5 and 9.9 lb (2.5–4.5 kg); head-to-body length is about 15.7 in (40 cm).
Both males and females are fitted with exceptionally long, thin tails that add another 16–24 in (40–60 cm) to their bodies. These monkeys have the distinction of being the smallest species belonging to the genus Macaca with the longest tails relative to their body size.
The potential lifespan for wild toque macaques is up to 35 years. However, the realistic lifespan for most of them is less than 5 years. Sadly, all three subspecies are susceptible to high infant mortality rates; furthermore, adolescent males frequently meet a tragic demise when they leave their birth group in a quest to join a new troop or form of a troop of their own. Those toque macaques who attain sexual maturity, researchers believe, have a greater chance of fulfilling their natural lifespan.
Lifespan for captive toque macaques is reported as 29 to 35 years.
Living in close association in a way that allows one species to benefit without harming the other.
The fur, hair, or wool of a mammal.
Visit the Glossary for more definitions
The pelage that cloaks the upper side of toque macaques varies in color according to subspecies. Generally, the coloring ranges from golden or orange-brown to yellowish or olive. Their furry underside is white, and wisps of white hair fan out from the monkeys’ large, scalloped, conspicuously protruding black ears. The long tail is dark on the upper side and pale white on the underside. An elongated hairless muzzle gives way to a prominent chin; the narrow lips are black. As they age, the faces of females become pink (varying shades from pale to bright, almost red). This pink coloration is especially obvious in dry-zone toque macaques. Males have ho-hum tan hairless faces.
One of the most distinguishing features (if not the most distinguishing feature) of toque macaques is their unkempt, moppy hairdos. Nature has unapologetically teased a whorl of hair at the crown of each monkey’s head. This decorative whorl has been compared to a brimless cap (called a “toque”).
Like their fur coat, coloring and the outrageousness of their whorly hairdo differs according to subspecies and the regions where these monkeys live.
- Dry-zone toque macaques are cloaked in a chestnut-colored coat with a white underside. Their whorly crown of hair fans out like a whisk broom; the short hairs are golden brown. This might be the least unkempt of the three hairdo styles.
- Wet-zone toque macaques are cloaked in a dusky yellowish coat that gives way to a dark brown color on the rump; the underside is white. Their hairdo may be the most unruly of the three subspecies, with long hairs sticking out randomly from the crown of their head (think of a serious case of “bed head”).
- Highland toque macaques are cloaked in a golden-brown coat with grayish-olive hues with a white underside. Their wild, long-haired, straw-colored whorl is somewhat reminiscent of a hairdo favored by songstress and international pop culture icon Cyndi Lauper during her punk-rock phase.
Toque macaques are mostly frugivorous; that is, they eat lots of fruits. However, their consumption of insects along with the occasional reptile, bird, or mammal—such as the Indian palm squirrel (Funambulus palmarum) and the Asiatic long-tailed climbing mouse (Vandeleuria oleracea)—makes them omnivores.
Flowers, buds, leaves, seeds, nuts, and mushrooms complement their meal plan. One of toque macaques’ favorite meals, of the 40 different types of trees that provide their nourishment, comes from the flowering plant commonly known as the golden shower (Cassia fistula). The drooping clusters of yellow flowers are irresistibly succulent to the monkeys.
In the dry zone, toque macaques eat the so-called stone fruits of the understory shrub Zizyphus, along with ripened figs of the Ficus tree and fruits and flowers of the flowering plant Cordia.
During the dry season when water obtained from their food sources is not enough to sustain them, toque macaques venture daily to watering holes.
Toque macaques are savvy opportunists, or scavengers—depending on your point of view. They are known to pick through garbage, looking for anything edible, left at human campsites. These monkeys are sometimes seen near human dwellings that abut a patch of forest, where they brazenly raid fruit plants (including plantains, pineapples, mangoes) and other crops (including rice, cocoa, and coconut) during daylight hours and then retreat to the forest at night. Toque macaques’ cheek pouches conveniently allow them to store food for later eating—particularly useful when “dining and dashing” with their stolen bounty.
A lack of fear toward humans or toward humans’ canine companions bolsters the monkeys’ raiding escapades.
Toque macaques live peaceably with other species (excepting humans), often befriending these animals. They enjoy commensal relationships with two species of monkeys: Hanuman langurs, also known as gray langurs (Semnopithecus entellus), and purple-faced langurs (Trachypithecus vetulus). Toque macaques often forage with purple-faced langurs, but the two species eat different foods, so there is no competition for food sources.
Behavior and Lifestyle
Toque macaques are diurnal animals—they are active in daylight hours. They are both arboreal (they spend much of their time in trees), and terrestrial (they are also found on the ground). While in the trees, they travel quadrupedally; that is, on all four limbs. On the ground, they walk on their digits. If necessary, such as when they are carrying food in their hands (these monkeys have superb dexterity), toque macaques can walk bipedally (upright), which is a testament to their agility.
Much of their day is spent foraging. Lower-ranking individuals are forced to forage for food in poorer resource areas, displaced by dominant individuals who claim better areas for themselves.
These monkeys may feel more comfortable foraging in the trees where they can avoid (or at lessen their risk to) their many predators, who include mugger crocodiles (Crocodylus palustris), leopards (Panthera pardus), Indian pythons (Python molurus), Russell’s vipers (Daboia russelii)—and humans. Their safety measures include selecting sleeping sites that are high in the forks of trees far from the central trunk, sleeping huddled together, and changing their sleeping site each night.
When foraging on the ground, safety measures include traveling together as a compact group and avoiding open spaces whenever possible. Should they detect danger, these monkeys will shove food into their cheek pouches using both hands, for later eating, and flee to safety in nearby trees. If they find themselves in dense foliage when danger presents, toque macaques are known to “freeze in place.” Perhaps most impressively, these monkeys—who are skillful swimmers—are known to hide beneath the water’s surface to escape a predator. They also appear to take great joy in splashing around in the water together.
Individuals are known to defend their territory against outside groups of toque macaques.
Macaca, the genus to which each of the three toque mancaque subspecies belongs, is the Portuguese word for “monkey.”
Toque macaques are excellent swimmers and will dive underwater to forage for their favorite plants.
Toque macaques befriend other species. It is not unusual for toque macaques that live near humans to befriend and groom the family dog.
Toque macaques are social animals who live in multimale/multifemale family groups, known as “troops.” Troop size ranges from 8 to 40 individuals, with an average troop size of 21 individuals. About half the members of a troop are adults; the other half comprises juveniles or infants. Members abide by a strict dominance hierarchy, with the oldest male being the alpha (or dominant) member and the troop’s leader, followed by other adult males, subadult males, adult females, and juveniles. Infants are born into their social classes based on their mothers’ hierarchal position in the troop.
In larger troops, tempers are known to flare and the ensuing drama can lead to in-fighting. Fights between individuals, often involving adults and subadults, may result in facial wounds, eye injuries—even broken arms.
Females, who would normally remain with their birth group, flee these hostile situations, particularly when they are being harassed by an alpha male. Males typically leave their birth group just before reaching adolescence, between 6 and 8 years old. If they don’t depart on their own volition, they are forced out. Their absence reduces the possibility of in-breeding and allows the current alpha male to retain his position in the troop. Leaving their birth group is the only path for young males to possibly find a position as alpha in another group—assuming they don’t succumb to environmental dangers during their quest.
Wildlife biologists have recorded 30 different vocalizations for toque macaques. Each of these nuanced calls conveys a specific meaning. The most common vocalizations include the following calls.
- Loud call: Sounded by an alpha male; used to maintain adequate spacing between members and to let his group know that it’s time to move on from their foraging site.
- Warning or alarm call: Sounded by individuals to alert others to potential danger.
- Scream call: Sounded by individuals when approached by a toque macaque from an outside group.
- Food call: Sounded by individuals upon discovering a desirable foraging site rich with food sources.
- Other calls accompany daily activities, such as playing.
Facial expressions are important indicators of mood or intent in the three subspecies. Contrary to its appearance, the fear grimace, which resembles a smile, is meant to appease or reduce escalation in aggressive encounters. Lips are retracted, revealing the toque macaque’s clenched teeth. An open-mouth stare is meant as a threat—and is not indicative of a state of awe; the monkey’s mouth is agape—open—but the teeth are not visible. An intense stare accompanies this expression.
As with most nonhuman primates, social grooming is an important activity among members that helps foster social bonds. Juveniles learn social bonds by playing in groups with other members who are the same age. They learn further life skills by watching older members of their troop.
Excellent stereoscopic vision (depth perception) and color vision allow toque macaques to easily discern objects. In fact, they rely more on their vision than they do their sense of smell when identifying specific food sources. Olfactory communication is still important, however. During breeding season, females secrete a pungent mucous from their vagina to let males know that they are ovulating and wish to copulate.
Female toque macaques reach sexual maturity (capable of conceiving and bearing offspring) at age 5; males lag behind a little bit, reaching sexual maturity (capable of siring offspring) at age 7. Breeding season occurs between July and September; the exact month varies with location of subspecies. During breeding season, females come into estrus (the period when they are most fertile and likely to conceive) once a month.
Toque macaques are polygynandrous, a scientific and polite way of saying that they are promiscuous: both males and females take multiple mating partners. If a female’s pungent vaginal secretion were not enough enticement to attract a male mating partner, the area surrounding her anus and genitals (known as the perineum) becomes bright red and swollen—guaranteeing male attention. While females might send out an invitation to copulate, males always initiate mounting. The copulating couple typically seeks out privacy for the act, but younger males—opportunists—often linger nearby, hoping for a chance to mate with the female once she and her partner are finished.
Despite a troop’s dominance hierarchy, copulation is not restricted to dominant males. That said, researchers report that it’s possible for a single alpha male to father all of the troops’ offspring—now that’s virility! The likelihood of infants surviving to reproductive age is linked to their mothers’ hierarchy among other females in the troop. A female with a high social status is likely to have a higher birthrate then females with a lesser rank.
After a five- to six-month gestation period (pregnancy), a female gives birth to a single infant. The interval between births is about 18 months. Infants are considered weaned at about 6 months old and are considered independent at age 2.
For the first two months of their lives, infants cling to their mothers. During this period, mothers teach their young important life skills. Mothers are the primary caregivers and protect their young. Fathers do little to help, likely because they cannot be sure that they sired the offspring. Males will, however, break up any fights that occur between juveniles.
A researcher’s account of highland toque macaques offers more specific details related to birth in this subspecies. As reported, births rarely occur during the day or on the ground. As she prepares for childbirth, a female isolates herself from her troop, putting a distance of about 0.062 mi (100 m) between herself and other troop members. Standing upright, she uses her hands to assist the delivery of her infant. After licking her infant clean, the mother places her newborn at her breast to suckle; then she eats a portion of the placenta, which provides a significant source of protein. A troop’s alpha female takes the remaining placenta for herself to eat. A mother resumes foraging activity within 20 minutes after giving birth. Should her infant cry out for her—mothers and their offspring recognize one another’s voices—she returns to provide care and comfort.
Toque macaques play an important role in helping to regenerate their forest ecosystem. Thanks to their largely frugivorous diet, they disperse the seeds of the many fruits they eat—via their feces—thereby encouraging new plant growth.
Toque macaques are listed as Endangered by the International Union for Conservation of Nature (IUCN, 2015), appearing on the IUCN Red List of Threatened Species.
Extreme habitat loss and habitat fragmentation have taken a grave toll on all three subspecies. More than half of these monkeys’ environment has been razed and converted for agricultural use, tea plantations, logging, and firewood. This devastation of habitat has forced toque macaques to venture close to human settlements, where they sift through garbage piles and spent campfires looking for food. They’ve become brazen crop raiders, a practice that has earned them the reputation as pests, causing farmers to set poison bait and traps to rid themselves of these unwelcome visitors. Furthermore, farmers routinely shoot these endangered monkeys on sight.
The illegal pet trade has taken a heavy toll on toque macaques, particularly the dry-zone and wet-zone subspecies. Countless others have been shot to death—used for target practice—by the Sri Lanka Army and by a militant organization known as the Liberation Tigers of Tamil Eelam (LTTE).
Toque macaques are listed in Appendix II of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
As is often the case with endangered species, however, laws created to protect them are largely ignored and difficult to enforce. Furthermore, out of all the wild animal species native to Sri Lanka, toque macaques are the only animals not afforded any protections under local law. No doubt, their reputation as crop pests has been a detriment to their protection status.
Conservation International is one environmental group working to improve local sentiment toward these stigmatized monkeys. The organization’s approach includes creating community education programs (that foster an appreciation of each of the three subspecies and the importance of saving them from extinction), creating new economic opportunities for 15,000 people living near protected areas, introducing alternative cooking technologies, and planting thousands of trees. In 2010, Sri Lanka issued a mandate to increase its forest cover from 23 percent to 36 percent.
At present, dry-zone and wet-zone toque macaque populations occur in numerous protected areas (reserves and national parks). No populations of highland toque macaques are found in such areas, however.
Written by Kathy Downey, June 2019