There are no known adverse effects of Chiropotes satanas on humans.
Brown-bearded sakis avoid predation largely through occupying the highest levels of the forest canopy and through their large body size. Quadrupedal leaping is also a helpful predator avoidance mechanism allowing a speedy and difficult to follow getaway. Harpy eagles, jaguars, and humans are the primary predators of Chiropotes satanas.
Known Predators:
Brown-bearded sakis are marked by bulbous temporal swellings, long bushy tails, and short body hair unlike the long, shaggy hair of their relatives in the genera Cacajao and Pithecia. Brown-bearded sakis are distinguished from the closely related Chiropotes albinasus by their larger black beards and their black noses. The two identified subspecies are primarily black except for the light yellowish-brown to ochraceous coloring on the back of C. s. chiropotes and the dark brown to black back and shoulders of C. s. satanas. In both subspecies, as well as in C. albinasus, males have distinctive, pink scrota and females have pink vaginal lips. Black-bearded sakis are slightly sexually dimorphic with an average weight of 3 kg in males and 2.6 kg in females. Head and body length ranges from 327 to 480 mm and tail length from 370 to 463 mm. Their hindlimbs are slightly longer than their forelimbs, resulting in an intermembral index of 83. They have a small thumb lacking true opposability. The foot tends to deviate laterally and the tarsal bones have increased mobility, a trait associated with their habit of hindlimb suspension while feeding.
The jaws of brown-bearded sakis have specialized anterior dentition for opening thick, woody, husked fruits. Adapted for powerful crushing, they have strong jaw muscles, low, flat molar teeth, broad canines, a deep robust mandible, and a dense maxilla without a maxillary sinus.
Range mass: 2.6 to 3.2 kg.
Range length: 327 to 480 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
There have been limited long term studies on Chiropotes satanas, so no available information on lifespan in this species. Related species have been recorded living up to 20 years.
Chiropotes satanas is typically found in primary tropical rainforests. In Brazil, members of this species are found in terra firma forests and occasionally in regenerating forests. In Suriname, C. satanas has been seen in rain forests, mountain savannah forests and occasionally in gallery forests. They rarely descend to lower canopy levels and the forest floor. Chiropotes satanas individuals spend 60% of their time in the middle and upper levels of the forest canopy.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: rainforest
Other Habitat Features: riparian
Chiropotes satanas (brown-bearded saki) is found throughout much of northern Amazonia and the Guianas. There are two recognized subspecies: C. s. satanas is endemic to Brazil occupying a small area around the Tocantin river near the mouth of the Amazon, C. s. chiropotes occurs more widely north of the Amazon river and east of the Negro and Orinoco rivers. The total geographic range of C. satanas has been estimated at 62,911 square kilometers.
Biogeographic Regions: neotropical (Native )
Primarily a sclerocarp frugivore, Chiropotes satanas feeds primarily on immature seeds particularly covered in hard pericarp. They have been recorded to eat at least 53 different species of seeds and are especially fond of the Brazil nut family (Lecythidaceae). Their specialized anterior dentition allows them to open very hard fruit for the young, relatively soft seeds. By eating young immature seeds C. satanas not only gets at a resource unavailable to many other primates, but also may avoid toxins that only occur in more mature seeds. The ability to break open hard shells of immature seeds and fruit also gives C. satanas an advantage by allowing them first pick of fruiting trees often not leaving many to ripen to stages that other species can eat. The opening of hard fruits and shells by C. satanas is accomplished by first biting a hole into the fruit at the edge of the operculum, then using it’s procumbent incisors to pop off the operculum to get to the seeds inside. The powerful wedge-shaped canines of C. satanas, rather than the incisors, are used when opening very tough foods with thick, hard seed pods.
The most efficient seed predator of any monkey species, C. satanas> individuals have been observed consuming 66% of their diet in seeds. They compliment this diet with ripe fruit, flowers, leaf stalks, and arthropods. Studies in Brazil, Surinam, and Venezuela showed 10 taxonomic orders of arthropods and 85 different plant species being exploited. The most common arthropods eaten are caterpillars, termites and gall wasps. Arthropod consumption in C. satanas is usually fairly low throughout the year peaking one to three times a year during temporary spikes in prey availability. When capturing prey, C. satanas often exhibit dexterity and agility. For example, individuals can remove gall wasp larvae from galls 4 mm in diameter, and others rest their arms, allow ants to climb onto them, and then eat the ants off their hair.
Captive individuals often drink by cupping their hands to pick up water then suck the fluid from their hands. Although not recently recorded in the wild, it can probably be assumed that this is characteristic of the species since the scientific name Chiropotes, coined by Humboldt, means “hand-drinker.”
Interestingly, geophagy (the ingestion of earth, soil or clay) has been observed on two occasions by C. satanas. In both instances individuals were seen eating a few handfuls of termitaria without any inspection (as they would do when hunting insects) indicating that the ingestion of the termitaria was the purpose. This is thought to be an adaptive behavior for a number of reasons: mineral supplementation, absorption of harmful toxins, and for easing gastrointestinal disorders such as diarrhea and excess stomach acidity.
Brown-bearded sakis spend 130 to 200 minutes a day feeding, not including travel time between food resources. While foraging they split up into smaller feeding units of around nine individuals and move rapidly in a cohesive manner between groups of feeding trees. Once the troop has arrived at a new feeding area they then split up, staying within a radius of 50 to 75 m, well within range of each others vocalizations which they keep up constantly. The pattern of rapidly moving between food trees with periods of relatively short but intense feeding bouts observed in brown-bearded sakis is to be expected of a specialized species concentrating on widely dispersed, seasonal, high protein food sources.
Animal Foods: insects; terrestrial non-insect arthropods
Plant Foods: seeds, grains, and nuts; fruit; flowers
Primary Diet: herbivore (Granivore )
As frugivores, brown-bearded sakis play a role in distributing seeds of fruiting trees. Their role as seed dispersers, however, is decreased by the fact that they eat immature seeds of unripe fruits. Their ability to get at immature seeds in unripe fruits also effects sympatric frugivorous species like Ateles paniscus and Cebus apella who eat some of the same fruits, but only when ripe. Brown-bearded sakis often live sympatrically with several other Platyrrhini species such as Alouatta seniculus, Saimiri sciureus, Saguinus midas, and Pithecia pithecia.
Ecosystem Impact: disperses seeds
Some groups of humans benefit from Chiropotes satanas by hunting them for meat and body parts. Humans also may benefit economically from keeping some black-bearded sakis in zoos.
Positive Impacts: food ; body parts are source of valuable material; ecotourism
Chiropotes satanas is considered endangered because of human induced habit degradation and hunting. The United States Endangered Species Act list lists C. satanas as endangered. The CITES appendices has both subspecies under Appendix II since 1977. The formation of protected areas may be improving the prospects for populations of Chiropotes satanas chiropotes.
US Federal List: endangered
CITES: appendix ii
State of Michigan List: no special status
IUCN Red List of Threatened Species: critically endangered
Black-bearded sakis use vocalizations and body language to communicate. As is the case with many arboreal primates, vocalizing is an important way to keep track of conspecifics in an environment with often limited vision. There have been no extensive studies on vocalizations of Chiropotes satanas, but some repeatedly observed vocalizations have been recorded. Weak chirps are associated with eating and satisfaction, and a shrill vocalization was recorded when a group was eating seasonally abundant caterpillars in eastern Brazilian Amazonia. A high pitch whistle, described as starting off as a sharp penetrating whistle, lasting for about a second and then cutting off, serves as a contact signal while a more intense version serves as an alarm call. A shrill bird like cry is also made when disturbed. Purring vocalizations are emitted by the female prior to mating and by the male while mating. The hybrid offspring infant described above made similar sounds when it wanted to nurse prompting the mother's help in finding the nipple. The infant's vocalization also provoked a similar vocalization from the mother which apparently excited the male. Loud cries by the infant disturbed the mother and father prompting close examination by both parents.
Tail wagging has been observed in a number of contexts. Considered a sign of excitement, it may also serve as a displacement activity and as a silent contact signal.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Little is currently known about the mating system of Chiropotes satanas in the wild. They live and interact mainly in multi-male multi-female social groups, monogamous groups have been observed rarely.
Mating has been observed in captivity although it was between a female Chiropotes albinasus and a male Chiropotes satanas, producing a hybrid offspring. Here it was observed that the female’s anogenital region became bright red to indicate sexual receptivity and that she made this visible to the male by lying in front of him and lifting her to exposing the red color. She also made a purring vocalization similar to one made by the male during mating.
Mating System: monogamous ; polygynandrous (promiscuous)
There is little information available on the reproductive cycles of Chiropotes satanas in the wild. Birth seem to occur at the beginning of the rainy season, in December or January. This coincides with the beginning of the fruiting season of several important species of Eschweilera trees that brown-bearded sakis exploit for food.
All other reproduction information for C. satanus is based on observations of a hybrid born to a female Chiropotes albinasus and a male C. satanas in captivity. These observations estimate a gestation period of four to five months. The hybrid offspring was weaned and capable of independent locomotion by the age of three months.
An interesting trait of C. satanas infants is their prehensile tail. Observed in the wild as well as with the captive hybrid, the tail is prehensile for about the first two months of life. It is used to cling to the mother. The tail ceases being prehensile at about 2 months old.
Breeding interval: Chiropotes satanas seems to give birth once a year.
Breeding season: In Surinam young were born at the beginning of the rainy season. This suggests breeding occurs from July to September.
Range number of offspring: 1 to 1.
Range gestation period: 4 to 5 months.
Range weaning age: 2 to 3 months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Most of the parental care comes from the mother. The reaction of a male Chiropotes satanas to the cries of his hybrid infant in captivity show a level of concern that could translate in the wild to pre-weaning protection. This cannot be truly known given that the offspring is a hybrid and in captivity forced to be in close contact. The mother nurses the infant and carries the infant on her until the young are weaned. Infants show some association with the mother after weaning, at 2 to 3 months of age, often retreating to her for protection when startled.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Protecting: Female)
The black bearded saki (Chiropotes satanas) is a species of New World monkey, native to the Amazon rainforest of South America, specifically to an area of north-eastern Brazil.[2] It is one of five species of bearded saki. Bearded sakis are medium-sized (50 cm), mostly frugivorous primates, specialised in seed predation.[3] The genus name Chiropotes means "hand-drinker" as they have been observed using their hands as ladles for scooping water into their mouths. This behavior is thought to be a way of maintaining and protecting their characteristic beards.[4] The black bearded sakis habitat has undergone heavy habitat fragmentation, making the future conservation status of the species uncertain.[5]
Black bearded sakis are endemic to the far eastern Amazon in Brazil, in a range restricted to a relatively small region from the Tocantins River in Pará east to around the Grajaú River in Maranhão (similar to the range of the equally threatened Kaapori capuchin). The natural home range of bearded sakis can vary from 200 to 250 hectares.[6] It is the only Amazonian pitheciid found east of the Tocantins River.[7] Studies show that bearded sakis can adapt to a reduction in their habitat.
Black bearded sakis can be identified by their thick black hair, distinctive beard that shapes the face, and a bushy fox-like tail. The tail is non-prehensible and they use quadrupedal movement for locomotion.[8] Black bearded sakis have some yellowish-brown highlights around the back and shoulders and can weight from 2 kg to 4 kg[5]. Males are slightly larger than females and also have a bulging forehead. Formerly the red-backed, brown-backed and Uta Hick's bearded sakis, the other member of the genus Chiropotes, were classified as subspecies or taxonomically insignificant variations of the same species called the bearded saki, but based on pelage differences and molecular analysis it has been recommended to treat them as separate species.[9] The black bearded saki is the only dark-nosed species of bearded saki with a blackish back, though some females and juveniles have a paler, brownish back.[10] The teeth have evolved for seed predation: these dental adaptations allow then to crack and access seeds in extremely hard pods. They open hard-shelled fruits in a specialized, efficient process using their teeth.[6]
Black bearded sakis are highly frugivorous, specialized in seed predation as 90% of their diet comes from fruits and seeds.[10] Black bearded sakis feed mostly on plants of the families Sapotaceae, Lecythidaceae, and Chrysobalanaceae, but they are known to feed on more than 100 species and are able to adapt their diets.[11] They complement their diets with fleshy fruits and small insects. Black bearded sakis use their strong canine teeth to crack open hard shells of fruits and nuts, enabling them to access the unripe seeds inside the fruits.[12]
They are social animals, commonly grooming and playing with one another, even with those of other primate species. Black bearded sakis can be found in troops of 20 to 30 individuals. Individuals of a troop will separate and rejoin throughout the day, have large home ranges, and travel long distances daily.[13]
Black bearded sakis spend most of their time resting, traveling and eating.[14] Black bearded sakis use mostly quadrupedal movement to move in the canopy of trees.[15] As infants the monkeys can be seen using their tail to grasp things, but lose the ability as they mature.
Bearded sakis have a gestation period of 5 months and produce one young at a time. They become sexually mature at 4 years old and have an expected lifespan of 18 years.[16] Black bearded sakis give birth to offspring every 2 years.[11]
Black bearded sakis are a critically endangered species.[17] Just over the last few decades urbanization in the Brazilian Amazon has brought with it highways, agriculture, and dams, creating an influx of habitat fragmentation, habitat destruction and poaching pressure.[17] Habitat fragmentation is rising as secondary roads increase and people move into uninhabited areas of the Amazon rainforest. Along with an influx of people the amount of agriculture required to support the area increases, augmenting the pressure for deforestation.
Studies reveal that black bearded sakis can adapt to habitat up to 3% the size of their original range.[11] However, it is unclear whether this behavioral flexibility is sufficient for the long-term viability of this species in fragmented habitats.[18] Forest fragmentation has resulted in behavioral changes that allow the species to adapt but could be detrimental for its conservation status in the long run.[14] Black bearded saki groups will not leave isolated patches of fragmented forest unless the bridge of secondary forest grows.[14] Groups in smaller patches of forest will tend to move and vocalize less while resting more.[14] Population density will increase as habitat size decreases, causing a positive tendency in disease among the black bearded saki population living in small patches.[14] This species also face a hunting problem for bushmeat and their tails used as dusters.
Bearded sakis living in small forest fragments are limited in their dietary choices because of the reduced number of plant species present, and therefore consume species that those individuals inhabiting continuous forests would ignore. Shifts in feeding patterns occur where fragmentation has been accompanied by selective logging of species used by black bearded sakis as food.[19] The ability to have a flexible diet and include seeds and unripe fruit helps this species survive in smaller forest fragments, but it appears that these conditions are unviable unless connectivity increases among the forest fragments and continuous forest in the landscape.[18] The future survival of the black bearded saki will depend on adequate meta-population and habitat management.[19] Habitat conservation is of top priority as this species has a particularly small range. The black bearded saki is considered the most endangered primate in the Amazon and is already locally extinct in a large portion of its original range.[16]
Studies performed at the Biological Dynamics of Forest Fragments Project study area have recorded the changes in behavior caused in black bearded sakis by habitat fragmentation. Groups of black bearded saki living in 10 hectare fragments of isolated rainforest showed a lack of reproduction in a period of 3.5 years.[14] This might be due to a lack of resources in these small isolated fragments of habitat. Smaller fragments of forest also result in higher population densities. The increased density of bearded saki monkeys in the small fragments may affect their health. Higher density groups living in forest fragments are more prone to parasites and disease than those others living in undisturbed areas.[14] It is unknown if the species will be able to reproduce and achieve healthy populations in the smaller patches of fragmented forest they are forced to inhabit.
{{cite journal}}: Cite journal requires |journal= (help) The black bearded saki (Chiropotes satanas) is a species of New World monkey, native to the Amazon rainforest of South America, specifically to an area of north-eastern Brazil. It is one of five species of bearded saki. Bearded sakis are medium-sized (50 cm), mostly frugivorous primates, specialised in seed predation. The genus name Chiropotes means "hand-drinker" as they have been observed using their hands as ladles for scooping water into their mouths. This behavior is thought to be a way of maintaining and protecting their characteristic beards. The black bearded sakis habitat has undergone heavy habitat fragmentation, making the future conservation status of the species uncertain.
