Geographic Distribution and Habitat
First described by Brazilian naturalist Georg Marcgrave in 1648, blond capuchins (Sapajus flavius) were rediscovered in 2006, incorporated into the known taxonomy, and given the scientific name Cebus flavius. In 2012, robust (or tufted) capuchins were separated out of genus Cebus in 2012 to form their own genus, Sapajus, to distinguish them from the gracile (or untufted) capuchins.
Blond capuchins or blonde capuchins, also called Marcgrave’s Capuchin Monkey for the aforementioned Brazilian naturlaist, live exclusively in a handful of small, isolated populations along Brazil’s Atlantic coast, in the Brazilian states of Alagoas, Paraíba, and Pernambuco. They prefer lowland coastal rainforest and swamps.
Size, Weight, and Lifespan
Size and weight averages are based on two individuals of each sex. For males, the average head and body length is 15.1 in (38.4 cm), with the tail adding an additional 15.5 in (39.4 cm). Males weigh 6.6 lbs (3.0 kg) on average. Female head and body length is 14 in (35.6 cm) on average, with an additional 15 in (38.2 cm) for the tail, and weighing an average of 3.9 lbs (2.2 kg). Exact lifespan figures are not known for the blond capuchin, but other capuchin species have been known to live an average of 40 years in the wild and 45 in captivity.
Blond capuchins are so named for the striking golden blond pelage over their entire body. They have a pinkish brown face, and their palms and the soles of their feet are black. Their prehensile tail (with a hairless patch on the underside of the tip) acts like a fifth hand, allowing them to hang from branches so that their hands are free.
Capuchins and closely related squirrel monkeys are the only New World monkeys with pseudo-opposable thumbs. While they are unable to rotate their thumb opposite their other digits, they have a very strong lateral grip between their thumb and index finger, making them more dexterous than any other primate on the continent. Capuchins (not squirrel monkeys) also have the ability to independently move each finger, adding to their dexterity.
True omnivores, blond capuchins favor fruits, seeds, and arthropods, and even sometimes eat frogs, nestlings, and small mammals. Sugar cane (raided from nearby plantations) is consumed as a fallback food when their preferred food isn’t as abundant.
Thanks to their unique dexterity and ability to use tools, capuchins can eat foods that are inaccessible to other animals. They smash nuts against rocks or branches or use rocks as a tool to smash them open. They also have the thickest tooth enamel of any nonhuman primate, helping them to crack open hard seeds and nuts.
Behavior and Lifestyle
Blond capuchins are largely diurnal, although they sometimes show crepuscular activity. As arboreal quadrupeds, they favor the lower to mid-canopy and understory of the forest, but often forage along the forest floor. They are dextrous and very smart, and even use stone tools. Examples of tool use by capuchins include using stones to crack open nuts, process seeds and fruit, and dig. Robust capuchins, which includes blond capuchins and their closest relatives in the Sapajus genus, spend the majority of their day feeding. They tend to rest more and travel less during the wet season, when resources are more abundant and less energy is needed to find food. During the dry season, robust capuchins consume more insects, as there is less fruit available to them.
What Does It Mean?
Specific calls that individuals in a troop make to warn other members of their group of imminent danger – such as predators.
Social grooming within a species.
Physically adapted to living primarily or exclusively in trees.
Appearing or active in twilight.
Active during daylight hours.
A recurring period of sexual receptivity and fertility in many female mammals.
Genus (plural, genera):
A biological classification, or ranking, of living beings that includes a group(s) of species that are structurally similar or “related” to one another through evolution.
The time of pregnancy from conception until birth.
A gelatinous secretion deposited into the female genital tract after copulation, which then hardens to form a plug. This provides the sperm a better chance to fertilize the egg.
The group into which an animal is born.
An animal or person who eats food of both plant and animal origin.
A thumb that can be placed opposite the fingers of the same hand. Opposable thumbs allow the digits to grasp and handle objects and are a characteristic of primates.
The fur, hair, or wool of a mammal.
A mating system in which both males and females have multiple mating partners during a breeding season.
The tail of an animal that has adapted to be able to grasp or hold objects.
A being who walks on all fours.
A branch of science that encompasses the description, identification, nomenclature, and classification of organisms.
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Daily Life and Group Dynamics
Blond capuchins are highly social animals, with an average group size of 18 individuals. Groups have more females than males, with 0.85 males for every female in a group on average. They are usually multi-male/multi-female groups, but groups with a single male also exist. Groups follow a linear hierarchy of dominance for both sexes, with the highest ranking male in a group above the highest ranking female. When they are sufficiently independent, which occurs at at least six years of age, males disperse from their natal group to form or join a new group. They usually join several new groups before eventually staying in one for the rest of their life. Females usually stay in their natal group, except for occasional adult females who may join a new group.
Allogrooming between females is a common form of social bonding. Allogrooming usually occurs from the higher-ranked individual to a lower-ranked one—i.e., the higher-ranked individual does the grooming. In fact, the dominant female is the only individual in a group that tends to perform more grooming than she receives. While antagonistic behavior between males occurs much more frequently than between females, adult males can and do still form close bonds with one another.
Although subpopulations of blond capuchins are small and isolated, different groups do sometimes interact. These interactions vary between benign curiosity and aggression, especially between the adult males of the groups.
Archaeological evidence suggests that capuchins have changed the way they’ve used tools over the last 3,000 years. They are the first nonhuman primates known to have long-term changing patterns of stone tool use.
Communication methods specific to the blond capuchin are not well documented. However, other species of robust capuchins tend to have a variety of vocal calls, including contact calls, used to reestablish connection to group mates when separated, and alarm calls. There may also be a specific call used by a lone male to signal his intent to form a new group. Olfactory communication is used by way of urine washing, in which an individual urinates on his or her extremities and rubs it on another individual, and chest rubbing, in which a male rubs his scent gland on a branch or other substrate. Robust capuchins have a large variety of facial expressions that are used to communicate, and they wag their tails when excited. Adult males exhibit a special reunion display after being separated for a time, in which they embrace and vocalize loudly.
Reproduction and Family
Mating is usually initiated by females. While in estrus (which lasts about five days), females solicit mating from the alpha male, and as their estrus period is ending, they may solicit mating from lower-ranked males in quick succession. Because both males and females mate with multiple partners, they are polygynandrous. Females indicate that they are receptive by raising their eyebrows, pouting their lips, cocking their head from side to side, stroking their chest, making quiet vocalizations, looking back over their shoulder, and sitting toward the male with their legs apart. These behaviors are the only outward indication that a female is in estrus, as there are no other obvious external signs. When the male reciprocates, he mirrors her actions, grins, and vocalizes. A salsa-style dance between the two then occurs, including 180-degree pirouettes and other movements. The two may look between their legs or over shoulder at each other to maintain a fixed gaze. Once the ritual is over, they mate. After copulation, a mating plug is left in the female, which increases the male’s odds of fathering an offspring.
Capuchins have no strict breeding season, but often time births with periods of plentiful food. Each female gives birth about once every two years. Gestation lasts about six months and usually results in a single offspring, with an average birth weight of 7.4 oz (210 g). For the first three weeks of life, young capuchins ride on their mother’s back. The mother spends the majority of her time for the first two weeks postpartum nursing and grooming the infant. After about three or four months of age, the care of the baby begins to be shared by other adult members of the group, both male and female. They continue to nurse into their second year of life, and reach reproductive maturity by age four or five years. There is evidence that blond capuchins may hybridize with the closely related black-striped capuchins (S. libidinosus).
Sexual behavior often occurs outside of reproduction for blond capuchins. It may occur between males to alleviate tension after fighting or the arrival of newcomers, and to form and strengthen social bonds. This type of sexual behavior for social purposes is similar to that seen in the bonobos of Africa.
Robust capuchins are well known for their role as seed dispersers. Blond capuchins and other members of Sapajus help to disperse about 80% of the seed species that they handle. Data on a closely related species, the golden-bellied capuchin, shows that this species deposits seeds a relatively long distance, a median of 980–1200 ft (300–360 m), from the mother tree, making them very important contributors to the first phase of seed dispersal. Given their similar diets and behaviors, this is likely also true of blond capuchins.
Blond capuchins are predators to the various insects, frogs, birds, and mammals that they consume. The only observed predators of robust capuchins are eagles and hawks, and the monkeys tend to be very wary of these raptors, sometimes sounding alarm calls even for harmless birds flying overhead. While it has not been observed, it is believed that blond capuchins may be prey to jaguars, pumas, coyotes, snakes, and crocodiles.
Conservation Status and Threats
As of 2008, the last time their status was evaluated, blond capuchins were considered Critically Endangered (IUCN, 2008), the last step before extinction in the wild. The population size is extremely small and has been estimated at between 180 and 1,000 individuals, which exist in an estimated 24–29 small, extremely fragmented subpopulations.
The International Union for Conservation of Nature (IUCN) assesses the threat level of blond capuchins as Endangered (IUCN, 2020), appearing on the IUCN’s Red List of Threatened Species. Their population size is an estimated 1,000 individuals, with roughly 500 mature individuals, which live in 29 small and extremely fragmented.
Major threats against blond capuchins include hunting for food, collection for pet trade, and habitat loss and fragmentation mainly due to coastal development, cattle ranching, and sugar cane farming. Capuchin monkeys (those of the genera Cebus and Sapajus) are unfortunately one of the most popular primate species kept as pets. As wild animals, they are well known to display dangerous and unpredictable aggression to their owners, even when they are separated from their mothers and raised by humans from an early age. In 2010, capuchins were specifically excluded from the definition of “service animals” under the Americans With Disabilities Act, and businesses and other institutions are not required to accommodate them as such.
Because populations of blond capuchins are very small and isolated, they are extremely vulnerable to population loss by disease. A 2017 study found that almost half (46%) of the blond capuchins tested were positive for microfilariae parasites, microscopic worms that infect the blood. With such a small, fragile population, any disease that weakens such a significant portion of the population is a huge risk to the survival of the species. Even if individuals are not killed outright by the disease, they may be sufficiently weakened so as to lower birth rates, become susceptible to other diseases, or not adapt well to times of food scarcity.
Blond capuchins are listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), protecting them from international trade except in very rare circumstances. They are not known to occur in any protected area, but there are populations within range of Guaribas Biological Reserve, Barra do Mamanguape Environmental Protection Area, and Manguezais da Foz do rio Mamanguape (an Area of Outstanding Ecological Interest), which may reside within these areas.
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- United States Department of Justice. 2017. Americans with Disabilities Act Title III Regulations. Part 36, Nondiscrimination on the Basis of Disability in Public Accommodations and Commercial Facilities. 28 CFR Part 36.
Written by K. Clare Quilan, February 2020. Conservation Status updated, Jul 2020.