As with some other species of primates, the posterior end of male western red colobus monkeys changes with age. Juvenile males display a swelling of the perineal organ to mimic that of a mature female during heat, though they are morphologically different. As fetuses and juveniles, western red colobus have a perineal organ that is bright pinkish-red, with a bright blue fake clitoris and some spots around the origin of the tail and anus. This vibrant coloration remains until maturity. The coloration of males changes drastically as they mature: the bright pinkish-red portion of the perineal organ turns a greyish-yellowish-red, and the bright blue darkens to a blueish-black. The perineal organ of males is covered with scaly keratinized skin that is stratified. Because juveniles look like adult females, they are protected against older, stronger males of the group.
Western red colobus monkeys use vocalizations to communicate. When predators, such as chimpanzees and leopards, are near, western red colobus call out. Immediately on detecting a chimpanzee, they call out in alarm but stop shortly thereafter. They then climb higher in the trees, up to strata 4 and 5, or higher than 26 m. When a leopard is spotted, western red colobus give an alarm call and several males then approach the leopard and drive it away. Juveniles exhibit a pink gential swelling much like the swelling of the adult females. This mimicry helps juveniles avoid confrontation with older, larger males of the group.
Communication Channels: acoustic
Other Communication Modes: mimicry ; choruses
Perception Channels: visual ; tactile ; acoustic ; chemical
Western red colobus monkeys are considered endangered by the IUCN. The subspecies P.b. waldroni is critically endangered and possibly extinct. Low population size is due to hunting for bushmeat and fur as well as habitat destruction from logging.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: endangered
There are no known adverse effects of Piliocolobus badius on humans.
Western red colobus monkeys are an important part of the bushmeat trade. It is difficult to enforce laws in national parks, where poachers hunt with little interference. The subspecies P.b. waldroni has been driven to or very near extinction due to poaching and the bushmeat trade. Western red colobus monkeys are also hunted for their coat, as they possess long fur with an appealing coloration.
Positive Impacts: food ; body parts are source of valuable material
Western red colobus monkeys are prey to chimpanzees and leopards. They may also act as seed dispersers during the dry season when they eat a higher proportion of fruits.
Ecosystem Impact: disperses seeds
Western red colobus monkeys are folivorous, consuming mostly young leaves but also mature leaves, seeds, unripe fruit and shoots. Members of the subspecies P.b. temmincki consume leaves of Terminalia macroptera, Celtis integrifolia, Erythrophleum guineense, Pterocarpus erinaceus and Dichrostachys glomerata as well as fruits and flowers at the end of the dry season when leaves have become hard. Western red colobus possess a unique digestive system in which a ruminant-like multi-chambered stomach digests cellulose.
Plant Foods: seeds, grains, and nuts; fruit; flowers
Primary Diet: herbivore (Folivore )
Western red colobus monkeys are found in western Africa. The subspecies P.b. badius, bay red colobus, is native to Cote d’Ivoire, Sierra Leone and Liberia. The subspecies P.b. waldroni, Miss Waldron's red colobus, is native to eastern Cote d’Ivoire and western Ghana. The subspecies, P.b. temminiki, Temminck's red colobus, is native to Senegal and is scattered through Guinea, Gambia and Guinea-Bissau.
Biogeographic Regions: ethiopian (Native )
Western red colobus are found in old growth rain forests at all levels of the canopy, from the ground to stratum 5 of the tree canopy, which is the tops of developing trees greater than 40m above ground. Western red colobus monkeys spend most of their time in the third or fourth strata (20 to 30m). The subspeices P.b. Temmincki resides in mountain forests and tropical rain forests and are also adapted to the dry forests of Senegal. The subspecies P.b. waldroni inhabits dense, tall canopied forests.
Range elevation: 0 (low) m.
Average elevation: 20-30 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest
Western red colobus monkeys have about a 30% mortality rate in their first 6 months. Between 6 and 12 months of age, they have a mortality rate of 18%. Due to chimpanzee predation, mortality rates are 28% between 18 and 24 months of age. Because females migrate between groups and males do not, females have a higher mortality rate than males. The lifespan of western red colobus is currently unknown.
Western red colobus are sexually dimorphic, and adult females are slightly smaller than adult males. Males weigh between 9.1 kg and 12.2 kg, whereas females weigh between 6.8 kg and 9.1 kg. Western red colobus are 45 to 67 cm in length, and their tail is an additional 52 to 80cm long. Their body is brown, grey or black in color, and their head and appendages are chestnut or red in color. Their pubic area is surrounded by white fur. Their coat is even in length. Western red colobus do not have a thumb, but rather have a bump in their place. They also have long fingers for grasping branches. In addition, male and female juvenile western red colobus exhibit similar genital swellings as mature females, and juvenile males do not yet show evidence of a penis or scrotum. There are three subspecies of Pilliocolobus badius, P.b. badius, P.b. temmincki, and P.b. waldroni, and each are slightly different in physical appearance. P.b. badius exhibit black foreheads and outer thighs, and they also possess an exterior nose elevetaed on a well padded base. P.b. waldroni possess more red on their outer thighs and forehead than P.b. badius.
Range mass: 6.8 to 12.2 kg.
Range length: 97 to 147 cm.
Sexual Dimorphism: sexes alike; male larger
Other Physical Features: endothermic ; bilateral symmetry
When predators, such as chimpanzees and leopards, are near, western red colobus call out. Immediately on detecting a chimpanzee, they call out in alarm but stop shortly thereafter. The group then climbs higher in the trees, up to strata 4 and 5, or higher than 26 m. When a leopard is spotted, western red colobus give an alarm call and several males then approach the leopard and drive it away. Western red colobus monkeys are also hunted by humans for their bushmeat and fur. The subspecies P.b. waldroni has been driven to or very near extinction by poachers because of their fur and meat. If P.b. waldroni is truly extinct, it would be the first recorded 20th century primate taxon to die off. There is, however, evidence of their continued existence, though this is limited to the forest between the Ehy Lagoon and Tanoe River of western Ghana.
Known Predators:
Female western red colobus monkeys choose which male(s) with which to mate, as they migrate from group to group. It is uncertain whether this species is monogamous or polyandrous.
Female western red colobus monkeys give birth to a single offspring every two years. Females leave their natal group, moving freely between groups of males, which remain in their natal group. Males of different coalitions demonstrate aggression as they fight for the mobile females. When females are ready to mate, they develop eostrogen-dependent swollen genitals that resemble a pink rosebud. This is not a permanent change. It is uncertain whether female western red colobus monkeys mate with a single male or multiple males. Characteristic of the subspecies P.b. temminckii, a male and female withdraw from the group, and the female lies susceptible to the male for copulation. P.b. temmincki also show distinctive seasonal breeding. The gestation period of western red colobus monkeys is 6 to 6.5 months. Females of P.b. temmincki do not make any sounds during copulation, whereas females of P.b. badius females do vocalize while copulating.
Range number of offspring: 1 (low) .
Range gestation period: 6 to 6.5 months.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Little information is available regarding parental investment of western red colobus monkeys, as they do not survive long enough to breed in captivity and few studies have focused on this aspect in the wild. General observations suggest no parental involvement occurs after birth. Mothers, however, defend, nurse and groom their offspring.
Parental Investment: altricial ; female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
