King Colobus, Colobus polykomos
KING COLOBUS
Colobus polykomos
Geographic Distribution and Habitat
The king colobus (Colobus polykomos), commonly referred to as the western black-and-white colobus or the ursine black-and-white colobus, is a primate species indigenous to West Africa, specifically Senegal, Guinea-Bissau, Guinea, Sierra Leone, Ivory Coast, and Liberia. Despite significant habitat destruction by humans, king colobuses are known to inhabit a variety of habitats, including rainforests, lowlands, and gallery forests.
In Africa, a lowland forest refers to a forest that occurs in a low-lying areas, often characterized by specific environmental conditions and tree species. Comparatively, gallery forests are defined by the band of trees that develop along the edge of a nearby watercourse, such as a river, stream, or wetland. Throughout their range, the most notable watercourses include Lake Chad, the Senegal River, the Gambia River, and the Niger River, the third-longest river in Africa, stretches approximately 2,600 miles (4,200 kilometers).
Access to a watercourse is vital for a primate, especially since water helps them regulate their internal body temperature, stay hydrated, maintain proper bodily functions, etc. Given that temperatures in western Africa can range anywhere between 79.9 to 96.8 degrees Fahrenheit (26.7 to 36 degrees Celsius), reliable access to water can have serious effects on an individual’s health, making or breaking their survival. Luckily, western Africa experiences a rainy season between the months of May to November, so collecting anywhere between 63 to 118 inches (1600 to 3000 millimeters) of rainfall is typical.
Size, Weight, and Lifespan
Male and female king colobus primates exhibit sexual dimorphism, that is, slight differences in appearance between the two sexes besides those that define their gender. Males are slightly longer and heavier than females and have a head-to-body length of about 26 inches (66.04 cm). Additionally, they weigh around 22 pounds (9.9 kg). Contrastingly, female king colobuses have shorter head-to-body lengths and weigh around 18 pounds (8.3 kg).
Both sexes have similar tail lengths, which range between 25 to 35 inches (63.5 to 88.9 cm).
In the wild, the average lifespan of a king colobus is around 20 years.
Appearance
King colobuses are a striking combination of white, black, and gray hues. While the majority of their body is black, other body parts, including the tail, shoulders, and head, are coated with white or gray hair.
Extending down to their shoulders, they also have long, white, seemingly wiry hair that resembles an ornate epaulette, or ornamental decoration often found on human high-ranking military uniforms. When the arms are outstretched, the epaulette cascades down their bodies, resembling a beautiful waterfall-like curtain of hair!
Despite having only four elongated fingers, king colobuses enjoy swinging from tree to tree in their strong, agile bodies. Their long, slender fingers and limbs are adapted to facilitate easy movement through the forest, and they typically depend on their body strength for nearly all daily behaviors.
Their tails are also non-prehensile, so they are unable to grip or grasp objects. Acting as a counterweight, the tail helps with balance and stability, ensuring they remain balanced across uneven surfaces, ultimately enhancing their agility.
Diet
King colobuses are herbivorous, which means that they mostly consume leaves, yet they also eat flowers and fruit. Plant types include: hackberry trees (Celtis durandii), boleko nuts (Ongokea gore), raphia palms (Raphia africana), African locust-beans (Parkia bicolor), and African nutmeg (Pycnanthus angolensis). Because nearly 30% of their feeding time is specifically dedicated to consuming leaves and seeds, on average, king colobuses eat between 4.4 to 6.6 pounds (2 to 3 kg) of leaves each day!
Anatomically, king colobuses have large multi-chambered stomachs to accommodate their unique diets, allowing them the ability to digest large quantities at once and break down the tough cellulose in their leafy diets. Because leaves have little nutritional value, individual animals need to consume large quantities at once so that their bodies can absorb the important nutrients, reaping the benefit of the plants. King colobuses, like all colobus monkeys, have multi-chambered, sacculated stomachs that allow them to efficiently break down the tough-to-digest cellulose in leaves through bacterial fermentation. To help with the breakdown, as they chew leaves, large salivary glands produce enzymes that act as buffers and help regulate the stomach’s pH.
Behavior and Lifestyle
On average, the home range of king colobuses spans from 59.3 to 205.1 acres (24 to 83 hectares), which is roughly eight times the size of Disneyland’s original park! Within their range, they travel approximately 2,090 to 2,723 feet (637 to 830 m) each day, and occasionally interact with other primate species, such as the Western red colobus (Piliocolobus badius), olive colobus monkey (Procolobus verus), and Diana monkey (Chlorocebus diana). King colobuses have a sympatric relationship with these species, meaning they coexist within the same geographical location and overlap in distribution. Because of this, they typically share resources and habitats.
King colobuses inhabit a wide range of elevations, sometimes reaching up to 14,764 feet (4,500 m)! Their preferred mode of transportation is swinging, so don’t be surprised if you see them flying from tree to tree! With four elongated fingers and a reduced thumb on each hand, each digit acts as a hook, giving them a strong grip to hold on to branches and vines. Considering how quickly they move, these physical adaptations are particularly advantageous.
Although swinging is their main form of transportation, king colobuses spend large amounts of their day resting or sunbathing. As an arboreal species, much of their diet can be easily accessed within the tree canopy, but on occasion, they will descend to the ground to forage for fallen foods. Digesting cellulose-rich meals requires a significant amount of energy and time, so rest is crucial. Without it, king colobuses are unable to properly ferment and digest their food, which can lead to serious health consequences, such as bloating, pain, ulcers, hemorrhages, etc.
King colobuses are generally diurnal primates, so they remain active during the daytime and rest at night when the sun goes down. Sleeping in groups, they choose trees high in the upper canopies that offer stability and protection from predators. Usually, they avoid sleeping near other primate groups, giving them exclusive access to various food sources. For protection, at least one troop member stays awake during nighttime, watching out for danger and predators. In the wild, the natural predators of this species are leopards (Panthera pardus), crowned hawk-eagles (Stephanoaetus coronatus), African rock pythons (Python sebae), etc.
Did you know that colobus primates do not have functional thumbs?
The term “colobus” originates from the Greek word “kolobos”, which translates to “mutilated”, “docked”, or “cut short” in English. This name reflects the absence of a thumb in all colobus species. Colobus monkeys swing high in the canopy via a method of locomotion called brachiation, or arm swinging, which reduces the energy needed to travel from one point to another—energy reserved for digesting their cellulose-rich diet. Instead, four long, hook-shaped fingers easily grasp branches. Thumbs might impede their energy-saving acrobatics.
The average group size of king colobus primates varies by location and habitat. For example, king colobuses in Tai National Park, located in Ivory Coast, have an average group size of around 15 individuals, while in the Cantanhez Forest in Guinea-Bissau, the average group size is between 2 to 10 individuals. Regardless, troops typically consist of 1 to 3 adult males, 4 to 6 adult females, in addition to juveniles and infants.
Compared to adult females, adult male colobuses are the dominant sex. Each troop has its own territory, so males are responsible for defining boundaries and protecting all other troop members from predators and threats. In fact, they may even form multi-male groups to increase their protection from predators. Larger groups can offer better defenses against predators, due to the potential ability to mob or attack threats. Unlike males, females do not perform territory defense. Contrastingly, they stay with the natal group to provide protection to infants and juveniles.
Females inhabiting a troop often engage in a behavior known as female philopatry, which is when individuals remain in, or return to, their birthplace. In brief, females born within a specified territory remain in that territory for their entire lives and raise their own families within the same territory. Developing close bonds with one another, females benefit from philopatry because it increases the likelihood of successful mating opportunities, increases the troop’s access to resources, helps to facilitate parental care for all young individuals, and provides more juvenile protection.
King colobus monkeys mostly communicate with two distinct types of alarm calls: roars and snorts. Roars are typically used to convey immediate danger, both to other troop members and to a predator. Snorts, on the other hand, act as more of a warning and may not be as urgent as a roar. For example, when a king colobus sees a leopard, they will snort first, followed by a roar. A snort may not be detected by the leopard and may only be heard by other troop members, potentially giving them enough time to disperse. However, once they roar, the danger should be considered immediate.
Territorial calls are also utilized by king colobuses, although their particular sound is hard to identify. These calls are often communicated between individuals across long distances, providing them with spatial awareness, or the ability to reference a body in relation to its surroundings.
The average gestation period for a king colobus, which is the time between conception and birth for females, is about 175 days. Typically, females give birth to one infant during the dry season, which lasts between the months of December and February.
Infants are born entirely white, adorned with thin, curly fur that covers their skin. This unique appearance makes it easier for adults and caregivers to notice and care for the troop’s infants, especially in times of distress or in danger. At around one month of age, an infant’s fur starts to darken, gradually mirroring that of an adult.
Throughout their infancy, nearly all infants are cared for by their biological mother or an alloparent, which is in this case any female in the troop other than the biological parent who provides care for an infant. Because females are typically philopatric, the occurrence of alloparenting is a natural and expected behavior for king colobus primates, especially since they are all likely to be biologically related.
Both male and female king colobuses reach sexual maturity between the ages of 2 to 5 years. After reaching sexual maturity, males typically leave their natal groups in order to avoid competition, particularly for food resources and mates, and inbreeding. By leaving, their aim is also to establish their own troop or assert their dominance in another. Comparatively, females may also disperse, but they eventually return to their natal groups when they are ready to breed, which typically begins around the age of three years old.
By consuming leaves, leaf-eating primates prune their tree sources, trimming away certain plant parts. Through this, they gradually create space within the vegetation, allowing sunlight to filter through and penetrate the canopy to plant life below. As a result, plant growth is stimulated through photosynthesis, the natural process by which plants convert sunlight energy into chemical energy. Furthermore, pruning prevents one plant species from outcompeting others, evidently increasing an ecosystem’s biodiversity and altering the forest’s structure.
As fruit-eating primates, king colobuses play a large role in maintaining the health and biodiversity of their ecosystem. As seed dispersers and pruners, their actions work to prevent a ripple effect that could lead to a reduction of plant populations and decreased seedling survival throughout a forest, ultimately impacting the survival of various plant and animal species.
In addition to pruning, king colobuses are noted for their ecological impact as seed dispersers. As they navigate the forest and forage for fruits and seeds, colobus monkeys disperse seeds by dropping, throwing, or defecating them. This behavior of moving seeds from one location to another facilitates the growth of new plants in different environments. Once these seeds take root, they recycle back into the soil and begin to grow. As they evolve, they increase the environment’s biodiversity, ultimately regenerating the ecosystem.
The International Union for Conservation of Nature lists the king colobus as Endangered (IUCN, June 25, 2019), appearing on the IUCN Red List of Threatened Species. According to the Red List, the primary threats to the survival of king colobuses are uncontrolled hunting for bushmeat, forest loss due to degradation, and forest fragmentation. Each of these factors has contributed to the drastic decline of the population by 50%.
Over the last 30 years, the human population throughout West Africa has increased by 120%. Occurring through Sierra Leone, Guinea-Bissau, Liberia, etc., each country has lost between 14 to 21% of its total forest cover, often due to habitat encroachment for agricultural purposes, even inside protected areas. For example, commercial logging and large-scale mining have directly affected the habitat of king colobuses, making them virtually uninhabitable.
Unfortunately, king colobuses are unable to survive in environments that lack biodiversity and are degraded. As an arboreal species, they require at least some mature forest to survive and thrive. Without these resources, they perish.
The king colobus 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.
The king colobus monkey is listed as Class A under the African Convention and is found in a number of protected areas throughout western Africa, including Sapo National Park and Grebo-Krahn National Park in Liberia; Gola Forest National Park, Loma Mountains National Park, and Tiwai Island Wildlife Sanctuary in Sierra Leone; Tai National Park in Ivory Coast; and Cantanhez National Park in Guinea-Bissau.
Unfortunately, laws against hunting and other illegal activities are poorly enforced in all countries within the king colobus’ geographic range. As a result, the species has disappeared from the majority of the protected areas in which it once occurred. Strict law enforcement is needed in these protected areas to ensure the survival of this species. Permanent research stations throughout the range would greatly assist conservation efforts.
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Written by Brooklynne Mitchell-Arno, June 2025