Wedge-capped capuchin

Appearance

Adult wedge-capped capuchins weight approximately 3 kg, but weight varies moderately with sex. They receive their name from a black triangle of dark fur centered on their foreheads. Generally this species is light brown to brown with yellow and gray tinges on varying parts of their bodies. Their “wedge cap” starts between the eyes and extends backwards to cover the top of the head. Their faces are hairless and surrounded by light brown or blonde fur.

Wedge-capped capuchins show similar levels of sexual dimorphism as other capuchin monkeys. On average, males weigh about 30% more than females. Additionally, males have relatively longer canines than females . Male maxillary and mandibular canines of males are on average 70% and 40% larger than female canines respectively. This may be indicative of male competition for females.Wedge-capped capuchins have been compared to tufted capuchins to discern the relationship between locomotion and skeletal proportions. Wedge-capped capuchins spent relatively more time running and jumping through the forest canopy while tufted capuchins spent more time walking and moving slowly. As such, wedge-capped capuchins have relatively longer limbs than tufted capuchins.

Naming

Wedge-capped capuchins sometimes rub themselves with millipedes they find while foraging. The monkeys rub the millipede against their fur, sometimes for as long as two minutes at a time. They also occasionally put the millipede in their mouths, remove them, and continue to rub them over their bodies. These capuchins often share these millipedes. The purpose of this strange behavior is difficult to determine. One theory is that the millipede, when threatened, releases noxious chemicals as a defense mechanism. These chemicals may act as insect repellants against mosquitos. This behavior is most common during the rainy season, when mosquitos are most prevalent.

Status

Wedge-capped capuchins are ranked as an animal as least concern on the IUCN Red List of Threatened Species. The wedge-capped capuchin is ranked as least concern because the animal is common and has a widespread range. Human hunting is one of the major threats to capuchin survival in some regions.

Behavior

Wedge-capped capuchins live in groups ranging from as few as 5 individuals to more than 30 individuals. The groups generally consist of one reproductively active adult male, several adult females and their offspring, and, in some cases, non-reproductive adult males. Juveniles generally make up about 50% of a groups population. The population structure is heavily skewed toward females. There are approximately 2 females to every male at birth. This ratio increases to more than 4 adult females for every adult male. This is the result of both female-biased birth ratios and male migration behavior.

Birthrate in wedge-capped capuchins varies with age. Younger and middle-aged females give birth as often as once every two years. Older females may only give birth once every three or four years. It is important to note that both male and female wedge-capped capuchins live as long as 36 years.

In wedge-capped capuchins, males emigrate from their natal groups while females generally remain in the same group for the majority of their lives. Males generally leave their natal group between 3 and 6 years of age. Young males spend little time alone after leaving their natal groups and quickly integrate into a new group. Males prefer to join groups with a high ratio of females to adult males, as this maximizes their probability for future mating success. Immigrating males generally meet little opposition when joining a new group. Older females may migrate to new groups on rare occasions.

Habitat

Wedge-capped capuchins prefer undisturbed primary forests in which they can move through the canopy . They occupy the rainforests of northern Brazil and Venezuela, as well as the drier forests along riverbeds in Guyana, Suriname, and French Guiana. These habitats vary in terms of forest height, composition, and continuity. When wedge-capped capuchins have the option between dense high-canopy primary forests and more fragmented, lower forests, they generally inhabit the primary forests.

Food

Wedge-capped capuchins are omnivorous and eat both animal and plant foods. Foraging behavior varies seasonally, as well as with age and sex. In general, these monkeys spend approximately equal amounts of time exploiting animal and plant resources. The exception to this are infants that spend far more time foraging for plants foods than animals. Most of the plant food consumed is ripe fruit, the majority of which are figs. Their animal prey is almost exclusively invertebrates. Their prey consists of snails, wasps, caterpillars, grasshoppers, ants, birds eggs and many insects that inhabit palm crowns.

While males and females spend about the same amount of time foraging for insects, they exploit different types of resources. Males spend more time searching for insects on the surface of branches, while females search for most of their insects atop palm trees. There is little variation in plant material consumed between males and females. Also, adults and sub-adults eat more animal material than juveniles and infants.Food washing has been observed in non-human primates including macaques and capuchins. The primates will sometimes wash their sandy fruits and foods prior to eating them. This act has been described as an example of protoculture. Wedge-capped capuchins were shown to wash sandy food in four spontaneous occasions in both captive and wild populations. Urbani found that food washing was a response to certain circumstantial problems and not through imitation or learning, as argued in studies of other species.

Predators

Wedge-capped capuchins are ranked as an animal as least concern on the IUCN Red List of Threatened Species. The wedge-capped capuchin is ranked as least concern because the animal is common and has a widespread range. Human hunting is one of the major threats to capuchin survival in some regions.