Cebus xanthosternos

Geographic Range

Golden-bellied capuchins ( Cebus xanthosternos ) have a Neotropical distribution. The species is located exclusively in Southern Bahia, Brazil, and live within Atlantic forest patches. In the past, C. xanthosternos spanned a large area to the north and west of the Rio São Francisco. Currently, however, their range has been reduced to the area north of the Rio Jequitinhonha to the Rio Paraguaçú.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Cebus xanthosternos live in mangroves, as well as in patches of coastal deciduous dry forest and rainforest in Southern Bahia, Brazil. Within forest patches, members of this species aggregate in the mid-canopy and understory regions. Elevation ranges from 0 to 1,850 meters in this area, though the altitudes at which C. xanthosternos can be found is not documented.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• rainforest rainforest

• Other Habitat Features
• riparian riparian

Physical Description

All members of the genus Cebus have large eyes that face forward, round heads, and flattened noses. They also have prehensile tails that are used mainly in locomotion to grasp tree limbs and secure them as they move. Golden-bellied capuchins have long digits with nails, non-opposable forelimb thumbs, and opposable big toes. The dental formula is (I2/2 C1/1 P3/3 M3/3) x 2 = 36. Like other members of the genus Cebus , males possess canines that tend to be 16-22% larger than female canines. Golden-bellied capuchins are a tufted capuchin species. The “tuft” refers to the bunch of dark hair located along the crown of adult's heads. Two tufts may form that have the appearance of horns; juveniles lack these tufts. Their bodies are covered in either light or dark brown fur. Along the shoulders and stomach, their fur is a yellow gold shade. Their chests are either the same yellow gold color or a golden red. Golden-bellied capuchins have small bodies and their faces are light in color. The sides of their faces, along with their feet, hands, and the tips of their tails, are black. The fur along the upper part of their faces tends to be salt-and-pepper colored. Tail lengths can range from 37.5 to 49 centimeters, while body lengths range from 35 to 48.8 centimeters. Males (1.3 to 4.8 kg) are usually slightly larger than females (1.4 to 3.4 kg). The basal metabolic rate of the species has not been studied.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

Although the mating system of Cebus xanthosternos is not well known, it is assumed to be similar to the closely related species, Cebus apella . Cebus apella has a promiscuous multimale-multifemale mating system. In terms of mate selection, females prefer to mate with the alpha male, as he may provide the best protection to their young. Golden-bellied capuchins appear to be cooperative breeders.

In Cebus apella , mating rituals consist of performances in which the female stares at the male and raises her eyebrows. In addition, she moves her head back and forth and travels closer to him. At some point, she touches him, runs away, and proceeds to murmur noises. Though the male may seem uninterested at first, he may make eye contact and also emit noises following several more attempts by the female. The male and female then perform a dance, which involves them jumping and spinning in the air. After the dance, they mate, and then resume dancing for a short time. Studies have shown that competition between males for females is strong among C. apella . The alpha male tends to have the greatest reproductive success, though lower ranked males are also able to mate. The alpha female of the group attempts to be the sole mate of the alpha male, and she may use aggression against other females. Female C. apella show no physical signs of fertility. The timing of the estrus cycle for C. xanthosternos has not been studied, but may be similar to the female C. apella estrus cycle of 18 days.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)
• cooperative breeder cooperative breeder

Golden-bellied capuchins can mate and give birth any time of the year. Time between births may be similar to that of C. apella , at 22 months. Gestation periods last from 150 to 180 days, after which only a single offspring is born. The newborn weighs anywhere from 250 to 290 grams. Though weaning periods are not well known for C. xanthosternos , capuchins in general may begin weaning at 2 months and the process can continue until the offspring is about 11 months old. Independence from the mother occurs around 6 to 12 months of age. Cebus xanthosternos females reach sexual maturity around 4 to 5 years of age, but they may not give birth until they are around 7 or 8 years old. Males become sexually mature 6 to 8 years after their birth.

• Key Reproductive Features
• iteroparous iteroparous
• year-round breeding year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Parental investment of Cebus xanthosternos has not been studied. However, mothers provide the most parental investment in the genus Cebus . Offspring are helpless at birth and require much assistance and care from their mothers in order to feed, move around, and stay protected. Baby capuchins cling to their mother’s stomach or back. At about 2 to 3 months of age, the young leave their mothers for short periods of time in order to mingle with other offspring. It is also around this time that older siblings are able to “baby-sit” and carry the young around. When a young capuchin becomes separated from its mother, other capuchins help care for it until she returns. The young continue to remain closely associated with their mothers until they are around 6 months old. After this time, they are able to feed and move themselves around independently. Weaning, however, may continue until around 11 months of age. While young females of the genus Cebus tend to stay within their mother’s group as they age, males usually leave their birth group to join a new one around 2 to 4 years old.

Because the mating system of Cebus xanthosternos is likely to be a promiscuous multimale and multifemale system (based on the species’ presumed reproductive similarity to Cebus apella ), the paternity of offspring may not always be known. In addition, copulation occurs frequently between males and females, which makes it difficult to discern paternity and thus, paternal investment. However, alpha male C. apella do allow females and their offspring to feed on food he collected. In addition, all males, including the alpha, will pick up and carry around young who have become separated from their mothers. But, it has also been observed in the wild, that male C. apella will commit infanticide.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• post-independence association with parents
• extended period of juvenile learning

Lifespan/Longevity

The lifespan of Cebus xanthosternos in the wild is not known. In captivity, the species is expected to live longer than 30 years. Though the longest lifespan for C. xanthosternos has not been documented, a similar species, Cebus apella , can live as long as 45 years in captivity.

Behavior

While the behavior of Cebus xanthosternos has been largely undocumented, there are details available regarding the behavior of the genus Cebus . Capuchins are arboreal, diurnal, move in a quadrupedal manner, and tend to spend most of their waking hours foraging for food. Capuchins are also very good at swinging through trees, biped running, and leaping between trees. They live in small groups of 8 to 30 individuals of the same species with a sex ratio of 1:1. Groups have a social hierarchy. Among males there is a single alpha male and all other males within the group are lower ranked. Though the alpha male is not necessarily the strongest or biggest of the males, he is the most dominant. Groups often engage in social grooming, as a means of creating group cohesion; the dominant male is usually the most heavily groomed by other members of the group. At times when different groups overlap, alpha males physically defend their groups, resources, and territories. There is also an alpha female who has a higher rank than the other females. However, she is less dominant than the alpha male.

Cebus xanthosternos , like other members of the genus Cebus , also perform urine washing. Urine washing is a territory marking practice, in which the animals soak their hands with urine, and rub the substance around their bodies. This urine scent travels with them, and infuses their living space. In addition to the urine, capuchins also rub other scented objects on their bodies. In general, capuchins are excellent throwers and are quite intelligent and dexterous. They are also avid tool users.

• Key Behaviors
• arboreal arboreal
• scansorial
• diurnal diurnal
• motile motile
• sedentary sedentary
• territorial territorial
• social social
• dominance hierarchies dominance hierarchies

Home Range

The home range for this species has not been studied. It has been estimated that there are about 10.87 individuals per square kilometer in some areas.

Communication and Perception

Golden-bellied capuchins are rather noisy animals. They emit short and frequent yipping whines, which sound similar to a newborn pup. Their alarm call is a distinctive two-toned clunking. Some of their vocalizations sound similar to bird-like rising whistles. Chemical signals are used to indicate territory boundaries and sexual receptiveness. Touch and visual cues are also important in communication.

Suggested by their large eyes that face forward, they are also visually oriented animals with good depth perception. They have acute olfactory senses that enable them to recognize and distinguish scent marks left by members of another group. Being dexterous animals, tactile sensitivity is another important way these monkeys perceive their environment.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Golden-bellied capuchins are truly omnivorous, eating fruits, seeds, nectar, pith, stems, nuts, berries, flowers, leaves, bird eggs, insects, frogs, small reptiles, birds, bats, other small mammals, and even oysters and crabs found in coastal areas. The diet of Cebus , in general, is more varied than that of any other New World monkeys. Golden-bellied capuchins are extractive and manipulative foragers. Their foraging activities are often destructive because they rip apart branches and leaves. The hammering of nuts against branches, and their jumping noisily from tree to tree, can be heard for long distances.

• Primary Diet
• omnivore omnivore

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• eggs
• insects
• terrestrial non-insect arthropods
• aquatic crustaceans

• Plant Foods
• leaves
• wood, bark, or stems
• seeds, grains, and nuts
• fruit
• nectar
• flowers

Predation

Predators of golden-bellied capuchins include large felids (jaguars, pumas, and ocelots), venomous and constricting snakes (rattlesnakes and boas), and large raptors (eagles and hawks). Near streams and pools, crocodiles can also be dangerous predators. Studies show that group size influences the risk of predation. Individuals of larger groups experience less predation due to the increased vigilance of many eyes, and improved success of attacking the predator. When a potential predator is spotted, an alarm call is emitted to notify the other members of the community of imminent danger. Their coloration may make them difficult to see in their mid-canopy habitats.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

As granivores and frugivores, golden-bellied capuchins play an important role in dispersing the seeds of some forest plants. They benefit themselves, as well as others in the community, by forming large anti-predator groups. They take turns foraging and looking out for predators.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Golden-bellied capuchins are used as models for human research in many forms: pharmacological, biomedical, behavioral, social, and physiological. They are kept in zoos, and as exotic pets by some people. Also, they are hunted for food.

• Positive Impacts
• pet trade pet trade
• food food
• research and education

Economic Importance for Humans: Negative

There are no known adverse effects of Cebus xanthosternos on humans.

Conservation Status

According to the IUCN Red List of Threatened Species, Cebus xanthosternos has been reported to be critically endangered since 1996, mainly due to heavy hunting and habitat loss. Several conservation acts have been, and are currently taking place. The Una Biological Reserve currently protects the largest single population. This species is also present in Condurú State Park and the Canavieiras Experimental Station.

Other Comments

Previously, Cebus xanthosternos was classified as a subspecies of Cebus apella . They are now considered to be genetically distinct from C. apella , and therefore a separate species (Rylands et. al., 2000; Silva Jr., 2001; Groves, 2001; Groves, 2005).

Additional Links

Encyclopedia of Life

Contributors

Jane Song (author), University of Michigan-Ann Arbor, Erika Moses (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor, Tanya Dewey (editor), Animal Diversity Web.

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