SCHMIDT'S RED-TAILED MONKEY

Cercopithecus ascanius schmidti

Geographic Distribution and Habitat
The Schmidt’s red-tailed monkey is found in Central Africa in the countries of the Democratic Republic of Congo, Uganda, Kenya, Burundi, Rwanda, and central western Tanzania, with isolated populations in South Sudan and the Central African Republic. They live in a variety of habitats in Sub-Saharan Africa including tropical rainforests, swamplands, and montane forests.

Schmidt's red-tail monkey geographic range. Map: IUCN, 2019

Size, Weight, and Lifespan
Male red-tailed monkeys are larger than their female counterparts. Males stand at about 19 in (47.5 cm) tall and weigh around 9.2 lb (4.2 kg). Females are about 16 in (41 cm) tall and weigh around 6.2 lb (2.8 kg). When looking at this monkey, one will immediately notice the incredibly long tail that can measure up to 36 in (90 cm).

These monkeys can live to be 28 years old.

Appearance
The Schmidt’s red-tailed monkey has several different unique features. The species is named for their long red tails, which can measure up to twice the length of the rest of their body. While other subspecies of the red-tailed monkey may have different facial coloring, the Schmidt’s subspecies has a blue-gray face, a white heart-shaped nose, and white cheeks that resemble muttonchops. Their body features a white chest and a gray and red back.

Diet
A little over half of the red-tailed monkey’s diet is made up of fruit. They have large cheek pouches that can store almost as much food as their stomach. This adaptation allows the monkeys to practice “retrieve-and-retreat” methods during foraging, in which the monkey stuffs his cheeks with as much fruit as possible and then retreats to a secluded location to eat in peace without others trying to steal his food.

Red-tailed monkeys may also eat insects, flowers, buds, leaves, and gum.

Behavior and Lifestyle
Red-tailed monkeys are diurnal and arboreal, although adults will often descend to the forest floor to forage for fallen fruit.

These monkeys awake at sunrise and begin foraging. They spend most of the late morning and afternoon resting, grooming, and traveling, before foraging again in the evening. Studies reveal that red-tailed monkeys prefer to eat fruit in the evening while they forage for leave and bugs in the morning.

Activity budgets show that these monkeys spend about 30% of their time foraging, 35% resting and socializing, and 35% traveling.

What Does It Mean?

Activity Budget:  
A way to quantify animal behavior by observing an animal over an extended period and documenting activity.

Alarm call:
Specific calls that individuals in a troop make to warn other members of their group of imminent danger, such as predators.

Allomothering:
Individuals other than the biological mother of an offspring perform the functions of a mother (as by caring for an infant temporarily).

Cheek Pouches:
Pockets on the side of the head between the jaw and the cheek that some animals have to store food.

​Diurnal:
Active during daylight hours.

Dominance hierarchy:
A type of social hierarchy that arises when members of a social group interact, often aggressively, to create a ranking system. In social living groups, member are likely to compete for access to limited resources and mating opportunities.

Ecosystem:
A biological community of interacting organisms and their physical environment.

Natal group:
The group into which an animal is born.

Visit the Glossary for more definitions

Daily Life and Group Dynamics 
Schmidt’s red-tailed monkeys live in uni-male groups composed of one adult male, about ten females, and their offspring. The females have a dominance hierarchy; one monkey is on top, with her daughters ranking just below her, and with sisters, nieces, and cousins at the bottom of the hierarchy. There are also all-male bands that join female groups during breeding season. There can be a wide range of group sizes, with some groups numbering as high as 50 individuals. Different groups may temporarily join together to forage, which provides them with more protection.

Fun Facts

Schmidt’s red-tailed monkeys often associate with other monkey species, including blue monkeysgrey-cheeked mangabeyswestern red colobuses, and mantled guerezas, to increase foraging efficiency.

Communication
Red-tailed monkeys have several vocal communications including trills to display submissiveness, chirps to identify family members or to sound an alarm, and different types of growls, screams, and hacking calls during fights with other monkeys. They also have a special warning call for birds of prey in which the adults will rapidly shout “ka” until the bird passes by.

A red-tailed monkey looking to intimidate a rival will stare at his target, emphasizing his brightly colored eyelids, open his mouth without showing his teeth, and bob his head up and down.

Family members greet each other by rubbing muzzles up against one another.

Reproduction and Family
Schmidt’s red-tailed monkeys breed year-round, but their peak breeding season occurs between November and February. The single dominant male mates with all of the adult females in the group, but roving bachelor males will sometimes secretly mate with the females. Pregnancy lasts about 6 months, after which a single infant is born, although twins have been observed on very rare occasions.

Females practice allomothering, in which all of the females in the group help raise the offspring. Males reach sexual maturity around the age of 6 and leave their family to join a bachelor group and hopefully someday control a uni-male group of their own. Females are able to mate after 4 or 5 years of life and will likely spend their entire life with their natal group.

Ecological Role
Red-tailed monkeys are major seed dispersers in their ecosystem. When they eat fruit, they will defecate the seeds far away from their parent tree and allow the new tree to grow without competing with its parent. This ensures a more diverse and healthier ecosystem.

Predators of the red-tailed monkeys include chimpanzees, raptors, and leopards.

Conservation Status and Threats
The International Union for Conservation of Nature gives the Schmidt’s red-tailed monkey a Least Concern assessment (IUCN, 2018), saying the species exists in a wide variety of habitats and is able to withstand hunting pressure from humans. The species is only threatened on smaller scales, such as isolated forest patches and communities.

There are local threats as a result of habitat degradation, loss and fragmentation, and agricultural encroachment. The rapidly growing human population in some parts of the range has led to habitat destruction related to farming, timber and fuelwood extraction, dam, road and powerline construction, mining, exotic tree plantations and human settlements. 

Schmidt’s red-tailed monkey is one of the least attractive African primates for hunters because they are alert, fast, and small in body size). However, they are affected locally by retaliatory hunting in response to crop-raiding, as well as by commercial bushmeat hunting.

Conservation Efforts
The IUCN calls for more research on the red-tailed monkey and an update on their assessment. There is no reliable population estimate on the species, nor is there enough information to know if the population is stable or not. The lack of information on the species is mostly due to the difficulty of traversing their habitat, which is often in dense jungles and swamplands.

​References:

  • Bektic, Lejla, 2009. Habitat preference and foraging behaviour in adult red-tailed monkeys (Cercopithecus ascanius). First cycle, G2E. Skara: SLU, Dept. of Animal Environment and Health.
  • https://animaldiversity.org/accounts/Cercopithecus_ascanius/
  • https://www.iucnredlist.org/species/4212/10654844
  • https://nationalzoo.si.edu/animals/schmidts-red-tailed-monkey
  • https://alltheworldsprimates.org/Members/Home/MasterPrimate.aspx?tid=396

Written by Eric Starr, April 2019