Booted Macaque, Macaca ochreata
BOOTED MACAQUE
Macaca ochreata
Geographic Distribution and Habitat
Booted macaques (Macaca ochreata) are one of seven macaque species found on the Indonesian island of Sulawesi. Specifically, booted macaques are found only on the island’s southeastern peninsula. Sulawesi is an Indonesian island situated between the Makassar Strait and the Banda Sea. The world’s 11th-largest island, it is comprised of several different peninsulas branching from a mountainous center, giving the island a unique orchid-like shape. The island features mountains, active volcanoes, waterways, and steep terrain, resulting in an incredibly diverse and complex array of habitats.
Booted macaques reside in mangrove and coastal forests, savanna habitats, and steep upland tropical forests reaching up to 2,625 feet (800 meters). Although they are adaptable and live in a variety of habitats, natural boundaries limit their geographic movement. The open ocean surrounds them, except to the north, where there is a hybrid zone with the Tonkean macaque (Macaca tonkeana).
Indonesia experiences a tropical, humid climate year-round. Temperatures average between 80.6 and 86 degrees Fahrenheit (27 and 30 degrees Celsius), while humidity levels typically range from 70% to 90%. Indonesia also experiences two distinct seasons, a rainy season and a dry season. Although the rainy season occurs between November and April, the heaviest rains come during December and January. Many areas receive around 79 inches (200.7 centimeters) of rain each year, but the precipitation levels can be unevenly distributed across different territories. In comparison, the dry season occurs between May and October, and these months receive only about 3 inches (7.62 centimeters) of rain. Due to these changing conditions, booted macaques must be able to roam large forest areas to find the proper food throughout the year.
Size, Weight, and Lifespan
As sexually dimorphic monkeys, there are slight physical differences between male and female booted macaques. On average, males weigh between 26.5 and 37.5 pounds (12 and 17 kilograms) and have a head and body length of 18.7 to 19.5 inches (47.5 to 49.5 centimeters). Comparatively, females weigh between 13.2 and 19.8 pounds (6 and 9 kilograms) and have a head to rump length of 15.6 to 17.6 inches (40 to 48 centimeters). Both males and females have similarly sized tails measuring between 2 and 3 inches (5 to 7 cm).
The current estimated life expectancy for wild booted macaques is unknown.
Appearance
The common name, booted macaque, comes from the light gray coloration on their arms and legs. In contrast to the dark fur on the rest of their bodies, it looks as though they are wearing boots.
Besides these areas, their fur color varies in shades of dark grey, brown, and black, and is typically uniformly colored throughout. Surrounding their blackish faces, they possess a gray mane, similar in color to their arms and legs. As they age, their hair will become sparser and lighter in color.
Both males and females have rounded faces, prominent brow ridges, and brown, or chocolate-colored, eyes. They have long muzzles and narrow, downward-facing nostrils. Like other macaque species, they have powerful bodies that allow them to leap and climb trees throughout the forest. Booted macaques spend time on the ground and in the trees; as such, they need to have strong muscles to support their movements. In addition to having strong limbs, they also have highly developed wrist and finger muscles in their hands. These features give them hand dexterity and a strong grip, which allows them to bear their body weight as they hold tree branches.
Extending down both sides of their neck, booted macaques also have specialized cheek pouches used for food storage. Because these cheek pouches roughly hold the same amount of food as their stomachs, they are particularly useful for rapid food collection and for transporting food across long distances. For example, when disturbed by predators or other macaques at a food source, rather than abandoning it altogether, they can rapidly shove their food inside the cheek pouches and flee to a safer location.
Diet
Booted macaques are largely fruit eaters, with fruits making up nearly 66% of their diet. Some of their preferred fruits include figs (Ficus carica), kapok (Ceiba pentandra), locally known as randu, and weeping figs (Ficus benjamina). Booted macaques have strong jaws that enable them to remove tough outer materials, allowing them to access the fruits inside.
In addition to fruit, the booted macaque diet consists of stems, flowers, and leaves. A small amount of their diet also includes small invertebrates or insects, but they are usually only consumed as supplementary food sources. Unlike plant products, insects and small animals can provide primates with essential proteins, fats, and minerals.
On occasion, booted macaques consume food products from cultivated farmlands and crop plantations. Although this causes conflict with some farmers, crop foods are too alluring and calorie-dense for wild macaques to pass up. Their diet is also highly adaptable, and because of the crops’ frequent accessibility and availability, there is little risk for such a large reward. In the area, the most abundant crop foods include cacao (Theobroma cacao), sweet potato (Ipomoea batatas), bananas (Musa x paradisiaca), and maize (Zea mays). Compared to their wild foods, these crops are calorically dense and are often considered equivalent to human junk food. Why pass up that opportunity?
Behavior and Lifestyle
Booted macaques are diurnal, so their sleep patterns and daily activity are dependent on daylight and the sun. An internal clock, known as the circadian rhythm, tells them when to wake up and when to go back to sleep. As the sun rises at dawn, they wake up and perform their daily activities. They are most active during the day and rely on sunlight to find food, navigate the forest, and communicate. With eyes adapted for bright light, they can see the world most clearly during the day. Prompted by the sun’s descent at dusk, their internal systems wind down, and they find rest at their sleeping site. Since they are most vulnerable to predators in open areas, they sleep on high tree branches hidden in forest cover. At night, predators like the reticulated python (Malayopython reticulatus) or the crested serpent eagle (Spilornis cheela) lurk through the forest in search of sleeping macaques.
Booted macaques are terrestrial and arboreal, meaning they spend time both on the ground and in the trees. They spend the majority of their time traveling between feeding sites throughout their range. Their average home range is about 153 acres (62 hectares), which is quite large. To provide perspective, that is about the same size as 116 football fields, which is massive! They move through the world quadrupedally, using all four of their limbs to navigate the forest. Like other macaque species, they are skilled climbers and can leap large distances. Besides traveling, they spend the rest of their time foraging, feeding, resting, and grooming.
Sir David Attenborough, the world-renowned naturalist, once said, “If you wanted to pick a monkey that was bright, adaptable, versatile, resilient, enterprising, tough, and capable of surviving extreme conditions and taking on all comers, the macaque would win hands down.”
Booted macaques live in multi-male, multi-female groups. Group sizes range from 12 to 53 individuals of varying ages and sexes, depending on the habitat. Typically, there are more females than males in a group. Although their numbers are small, males dominate the troop and determine their ranks through physical strength, ability, and size. Those with the highest rank have priority access to food and water, have the strongest influence over others, and get the best breeding opportunities. Although there are few studies of booted macaques’ social dynamics, these hierarchies are thought to be less strict than those of rhesus or Japanese macaques, meaning less dominant individuals may be able to access resources more easily. Daily interactions and social bonding solidify these relationships, but small slights can cause large-scale shifts in dynamics.
Although booted macaques live alongside tarsiers in southeastern Sulawesi, they interact with only one other primate species at the northern end of their range, the Tonkean macaque. In the Faruhumpenai Nature Reserve, booted macaques mate with Tonkean macaques and produce offspring. It is unknown whether these hybrid macaques can produce their own babies, further complicating conservation efforts.
Booted macaques primarily communicate through vocalizations, facial expressions, and body posturing. Whether communicating over short or long distances, they need to stay in contact, especially when in danger. Alarm calls are emitted exclusively by alpha males and consist of loud, high-pitched screams that sound like woops. Other, similar calls uttered by females are thought to help with group coordination.
When macaques are annoyed or agitated, they will make direct eye contact and flash their eyebrows as a warning to others. To avoid escalating these interactions to physical violence, booted macaques will bark or threaten using a throaty call that sounds like coughing. These aggressive calls and signals are most often heard or seen when males have their feeding interrupted. In contrast, mouth puckering or lip-smacking can often signal peace or submission, and is typically used to convey friendliness between individuals. Additionally, a high-pitched whine is made when a high-quality food item has been found or during mating. The most frequent call, however, is a short, bark-like coo used to maintain troop cohesion. This complex system of signals, similar to human language, supports the cooperation and survival of booted macaque groups.
Female booted macaques have a 36-day reproductive cycle, and during their ovulatory period, they show signs of sexual swelling. Swelling like this occurs during a female’s most fertile phase, and is used to attract male attention and increase mating opportunities. Dominant males usually prefer females with the largest swellings, and once selected, the pair mates and breeds. After a gestation period of about 24 weeks, females give birth to a single infant that weighs around 1.1 pounds (0.5 kilograms). Infants are born with brown fur, but as they mature and grow into adulthood, their coloration darkens, and their “boots” develop.
Macaque infants develop quickly and reach social and motor milestones four times faster than humans! From birth, infants have developed gripping skills and can cling to their mothers. With such grip, they hang on their mothers’ bellies for the first few months of their lives, before eventually transitioning to their mothers’ backs. Over the next few months, they will begin engaging in more social interactions. As their motor skills further develop, they begin to explore the area, gaining a sense of independence. Although they still feed from their mother, they simultaneously begin trying solid foods, attempting to forage for themselves. By the age of 6 months, they are nearly completely independent from the mother. Soon after they become sexually mature, males leave their natal group (the group they were born into) in the hopes of establishing themselves in a new troop, and females remain. Females reach sexual maturity between the ages of 5 and 6 years old, and males reach sexual maturity around the age of 7 years old.
As frugivores, booted macaques play a crucial role in maintaining the complexity and diversity of their environment, particularly as seed dispersers. When they eat fruits, they typically defecate, drop, or spit out the seeds into a new location. As the new plant develops, it increases the genetic diversity of its new location, which ultimately regenerates the forest. When they eat leaves or stems, they help regulate the amount of sunlight that reaches the forest floor, further improving ecosystem cycling. They may also be eaten by predators on Sulawesi, such as mongoose-like civets, raptors, large snakes, and lizards, supporting the populations of these equally important members of the ecosystem.
The International Union for Conservation of Nature lists booted macaques as Vulnerable (IUCN, 2015), appearing on the IUCN Red List of Threatened Species.
Forest loss due to commercial farming is the largest threat to this species, followed by legal and illegal logging and gold mining. As of 2023, a mere 10% of Sulawesi’s land was within a protected area.
Production companies focused on crops such as oil palm, cacao, bananas, maize, and cotton continue to reduce forest space. As resources in the forest dwindle and calorie-rich crops expand, the macaques raid crops from farms. To protect their livelihoods, farmers are known to poison the macaques, further affecting populations. Although many local farmers have changed their perspective on the issue, treating the monkeys less aggressively, some still consider booted macaques as pests. Without proper enforcement, education, and research, this critical conservation threat to the booted macaque will persist.
The booted macaque is 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.
Booted macaques are known to occur in at least five protected areas across their geographic range in Sulawesi: Tanjung Batikolo Wildlife Reserve, Tanjung Peropa Game Reserve, Rawa Aopa Watomanhai National Park, Pandang Mata Osu, and Faruhumpenai Nature Reserve. To protect the species and future generations, conservation should focus on continuing protection plans for these areas. Accurate data on the ecology and behavior of booted macaques is insufficient, so population surveys and ecological studies would also be very beneficial. Once conducted, they will provide better insight for their habitat requirements, which can be used to develop a species action plan.
As always, environmental awareness in human populations would be greatly appreciated. Conservation efforts and awareness will prevent future crop raiding, farmer retaliation, and discourage locals from keeping booted macaques as household pets.
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Written by Brooklynne Mitchell-Arno, April 2026