Geographic Distribution and Habitat
The mona monkey is found in the tropical forests of the Guinea region in West Africa. It is native to Ghana, Togo, Bénin, Nigeria, and Cameroon. The species was also introduced to the Lesser Antilles islands of the Caribbean Sea, most notably the island of Granada. Caribbean mona monkeys are mostly found inhabiting mangrove forests.
Mona monkeys live in warm temperatures averaging around 80°F (27°C) with little variation throughout the year.
Size, Weight, and Lifespan
From head-to-toe, male mona monkeys measure in at 20 in (51 cm) tall on average. Females are noticeably smaller at 16 in (41 cm) tall. Males are also heavier than females with an average weight of 11 lb (5 kg) compared to the average female weight of 8.8 lb (4 kg).
On average, mona monkeys live for up to 23 years in the wild and up to 30 years in captivity.
Mona monkeys and their close relatives all have distinctive faces. The skin on their nose and around their eyes is dark gray with a possible blue or purple tint. Their muzzle is pink and covered with thin white hairs. Their face is framed with a set of white sideburns that may have traces of yellow and gray in them. The slicked back fur on top of their head is often a mix of white, gray, and black fur.
The mona monkey has a colorful coat of fur with a brick-red back and white chest. The outer halves of their limbs are ebony-colored, as are their tails. Other than their size, there is no noticeable difference between males and females.
The majority of the mona monkey’s diet is made up of fruits and seeds. They also eat leaves, flowers, and insects. Mona monkeys in Granada have also been known to hunt snakes.
Mona monkeys are fast foragers. They store food inside their large cheek pouches and will continue to eat once they are safe from predators as well as potential food thieves. The mona monkey’s cheek pouches can store almost as much food as their stomach. These cheek pouches are a common trait among guenons (genus Cercopithecus).
Behavior and Lifestyle
The mona monkey is a diurnal (active during daylight hours) and arboreal (tree-dwelling) species that runs through the forest canopy on all four limbs, leaping from tree to tree.
Mona monkeys typically spend the morning foraging, followed by a midday rest mixed with grooming, playing, and other forms of socializing. They return to foraging in the late afternoon, after which they retire for the night.
Most groups live in polygynous societies, where a single male leads a group of around 10–20 females and their offspring. The largest group of mona monkeys ever observed had as many as 47 members. Males who do not control a group of their own either live alone or band together to form all-male bachelor groups. These groups usually only consist of a few members and live on the edges of uni-male territories waiting for a chance to overthrow the ruling male.
Being an especially social species, mona monkeys have developed a wide array of communication methods. When individuals lose sight of one another while foraging, they emit squeaking calls to make contact. Females emit “alarm sneezes,” that is, an alarm call that sounds similar to a sneeze. These monkeys can also sound the alarm using a high-pitch chirping call.
There are also two calls exclusive to males. Dominant males will make a loud “booming” call to establish territory. They also make low hacking calls to reorganize their group after a disturbance.
Female mona monkeys ideally give birth once every two years. They give birth to a single infant after 5 months of pregnancy (although twins have been observed on rare occasions). Babies are carried by their mothers for their first two weeks of life, after which they are strong enough to cling onto their mother’s back. The other females in the group will provide basic assistance in raising the baby, but the mother does most of the parenting on her own.
Babies are fully weaned off nursing after about a year. They will reach sexual maturity at about 3 or 4 years of age. Matured males leave their natal groups and go off on their own with the ultimate goal of controlling his own group. Females tend to stay with their families for life. On average, females give birth for the first time a little after their third birthday.
As frugivores, mona monkeys are valuable seed dispersers for their ecosystem. After eating a fruit, a monkey may travel a great distance before their food is digested. They defecate the seed far away from the parent tree, assuring a more diverse forest. Mona monkeys, and guenons in general, are even more effective seed dispersers than other animals thanks to their cheek pouches, which allow them to carry food farther than they could otherwise.
Pythons are the only confirmed predators of the mona monkey, but researchers believe that leopards and eagles may also prey on them.
Conservation Status and Threats
The International Union for Conservation of Nature listed the mona monkey as Near Threatened (IUCN, 2019), appearing on the IUCN’s Red List of Threatened Species. Mona monkeys are widespread in their range and able to adapt well to secondary habitats and human-modified forests with relative ease. However, the threat of large-scale habitat loss is expected to persist for the foreseeable future as the countries the mona monkey calls home are also some of the fastest growing economies in the world.
More egregious is the impact of hunting for bushmeat. Throughout West Africa, hunters have shifted their focus to smaller-bodied primates as larger-bodied species have declined or disappeared entirely, again primarily from hunting. As long as hunting pressure is not intense, mona monkeys might continue to withstand some of the on-going habitat degradation in their range. However, even given their high tolerance to human disturbances in their forests, some mona monkey subspecies have been eliminated in some regions.
This species is listed on Appendix II of CITES and on Class B of the African Convention on the Conservation of Nature and Natural Resources. It is known to occur in a number of protected areas, such as Korup and Takamanda national parks in Cameroon, Gashaka-Gumti, Okomu and Cross River national parks, and in Niger Delta in Nigeria, Lama Forest in Benin, and Fazao-Malfakassa and Togodo national parks in Togo, and Digya and Kalakpa national parks in Ghana. This species also occurs in a number of forest reserves, but increasingly this small-bodied primate is being hunted as the larger-bodied primate populations are being depleted, even in protected areas. Some mona monkey groups are protected in community forests, some of which are sacred forests, and urban parks in its range countries.
Written by Eric Starr, December 2018. Conservation status updated July 2020.