Guianan, Weeper capuchin
The wedge-capped capuchin or Guianan weeper capuchin (Cebus olivaceus ) is a capuchin monkey from South America. It is found in northern Brazil, Guyana and Venezuela. The genus Cebus is divided into several different species. However, taxonomists argue over the specific divisions within the genus, which are uncertain and controversial. Cebus olivaceus is known to dwell in tall, primary forest and travel over long distances during the day.
These primates are medium-sized monkeys with distinctive "wedge cap" markings on their head and slightly longer limbs than other capuchins for jumping through the forest canopy. Similar to other capuchin monkeys, the diet of wedge-capped capuchin primarily consists of fruits, invertebrates, other plant parts, and on rare occasions small vertebrates. They have also been known to rub millipedes against their fur, especially in the rainy seasons, as a potential means of mosquito repellent. Although this species is classified as an animal of least concern by IUCN Red List of Threatened Species, it falls prey to many predators in South America ranging from vultures to jaguars.
Cebus olivaceus is a polygamous species that lives in groups anywhere from 5-30 individuals, with a female biased sex ratios. The group is organized according to a pre-determined hierarchal system of dominance for both males and females. Although biological lineage is less of a factor of dominance for males than it is for females, due to male migration between groups. Wedge-capped capuchin partake in several behavioral mechanisms to assert and maintain dominance within the group including: infanticide, when an infant is deliberately killed; grooming, used to facilitate social rapport; and alloparenting, which is when members of the group care for offspring that are not their own.
Wedge-capped capuchins prefer undisturbed primary forests in which they can move through the canopy (locomotion and limb morphology). They occupy the rainforests of northern Brazil and Venezuela, as well as the drier forests along riverbeds in Guyana. 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. They are found north of the Orinoco River, south of the Sierra de Perijá and Venezuelan Coastal Range, and east to the Essequibo River in western Guyana.
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 (6 to 26 years old) give birth as often as once every two years. Older females (older than 26 years) 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.
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, but also palm nuts, seeds, berries, flowering buds, shoots, barks and gums. Their animal prey is almost exclusively invertebrates. Their prey consists of snails, arachnids, wasps, caterpillars, grasshoppers, ants, birds eggs, other small mammals and many insects that inhabit palm crowns. Some coastal populations may also include oysters, crabs, and other marine life in their diet.
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.
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.
