When disturbed, this species blushes a vivid scarlet and emits loud shouts that sound like laughter.
The name Uakari is pronounced wakari. Uakaris are gentle peaceable animals and prefer to keep up high in the canopy. There are three species of Uakaris; Cacajao melanocephalus, Cacajao rubicundus and Cacajao calvus.
Uakari’s are the only short-tailed American monkeys. Their faces, cheeks and top of the head is almost naked. There are three rather distinct types of colouration within the species: the subspecies Cacajao calvus calvus (White Uakari) is whitish in colour, except for its face which is scarlet. Cacajao calvus rubicundus (the Red Uakari) has a bright reddish brown to chestnut brown coat and an almost vermillion red face. Finally, the Cacajao melanocephalus (the Black-headed Uakari) has a chestnut brown pelt, but it’s face, shoulders, arms, hands, feet and lower surface of the tail is black.
Uakaris love being groomed, for example an Uakari soliciting grooming from a companion will typically come and lie alongside in a posture that signals its desire. The other will then spend several minutes picking through the fur to remove pests and debris. Especially from the head and upper back, which are not easy for the animals to reach, then the roles are reversed. The Uakari’s, although they occupy larger ranges, are also quite restricted in their preference for flooded forest habitats and are naturally quite low in number. The parts of the Amazon basin in which they reside are relatively little affected by habitat modification, but since they are riverside habitats access to them is possible from distant settlements and the monkeys are easy to kill.
The Uakari is the only South American monkey whose prehensile tail is actually shorter than its head and body, which measure 36 to 48 cm, the tail being only 15 to 18 cm long. The Uakari has a naked head which may have a bit of very sparse short hair, but in general they are completely bald. The monkeys bare face pokes out from a mass of shaggy hair which begins behind the ears and on its neck and the back of the head, so the Uakari looks rather like a bald monk with a cape. This utter baldness is accentuated by an almost complete lack of fat under the skin, making the face lean and bony. In the adult male the jaw muscles become big and bulky, and can be seen clearly underneath the bare skin, bulging out on the top of the skull. Uakaris are quieter than most monkeys. Their diet consists chiefly of fruit but they also eat leaves, insects and other small animals.
Uakaris have rarely been observed in the wild. Their superficial thickness of body has led people to suspect they are clumsy and lethargic, but on seeing how thin a shaved Uakari actually is, it is not at all surprising that they are in fact agile and active. In the wild they have been seem making leaps of twenty feet, launching themselves into the air with arms stretched forwards. On the ground they are somewhat ill at ease, walking with the hands partly flexed, and turned out sideways, but in captivity they invent games for themselves, sliding along the cage floor or turning back somersaults. When feeding they are very skillful, they hold the food in the whole flexed hand, between the index and middle fingers , or even between the hand and wrist.
They have projecting lower incisors and these are properly used for spearing the fruits which form part of their diet along with buds, leaves and seeds. Uakaris have been seen both in small troops and in large gatherings of about 100. They may go right up to the treetops but they come down to the lower branches when traveling through the forest.
Uakaris live to be approximately twenty years of age. They emit a sound much like hysterical laughter when annoyed. They are hunted by Indians in their homeland; adult Uakaris are eaten and the young ones are usually kept as pets. The Uakari has a fixed sorrowful facial expression, its body is covered with sparse long unkept hair and they betray their emotions by the colour of the bare skin on their heads and faces.
This bare skin is usually rosy pink, but in times of excitement or anger it flushes crimson. Only the black-headed Uakari has a naked black skinned face. Upon any suspicion of danger, the male Uakari’s will shake branches and perform a dance of imitation, beating with their hands and at the same time urinating so as to wet the entire ventral surface with urine. Adult Uakaris are physically powerful and when provoked they may at times be physically aggressive and dangerous. It is important to note that the equivalent term Bracyurus (their previous latin name) is sometimes used instead of the more commonly acepted term Cacajao.
The Bald Uakari is also known as Scarlet-fever faced monkeys. Bald Uakaris formerly ranged in the Brazilian forests from north of the Rio Solimoes river (from near the Tefe) almost as far west as the mouth of the Rio Ica river, northeast to Rio Japura river, and to the Rio Toapana river. Presently Bald Uakari’s are very vulnerable as result of pressures such as the drastic loss of habitat, hunting and live-collecting.
They are between 51 to 57 cm in size with a fairly short tail 15 to 16 cm long. Bald Uakaris have whitish-grey pelts and longer coats than the other species. Their faces are naked pink or red faces and turn scarlet red or crimson when they are frightened or angry, interestingly their faces turn paler if they are kept out of the sun and the more time they spend in the sun the brighter pink or crimson it will be. The Bald Uakari’s face may be harsh looking, but these monkeys are infact as shy, gentle and timid by nature as any of the other cebid monkeys. Bald Uakari’s eat mainly fruit but sometimes substitute their diet with spiders and leaves. They live in small troops consisting of several adults males, females and their young of different ages. They are shy by nature, diurnal, not aggressive and they adapt to vegetation changes with ease. Bald Uakari’s love water, they often take a quick dip or will swim for hours to cool of the summer heat. They are legally protected from capture and pet trade, but unfortunately their rainforest habitat is, like much of the Amazon, up for grabs and soon the Bald Uakari may be extinct.
These are some of the calls made by the Uakari.
chyook: This call is an intergrade of the hic and chick calls . This call occurs at the end of social grooming, a mother calling her young, and when there is a loud noise . This call is emitted by adult females .The receiver will respond with hics, chyooks, or chicks .
chick: This call occurs in a series or as one note. It is heard when there is a loud noise or when there is a potential predator. This call is emitted by both sexes from older juveniles on up. This call will elicit chicks on the part of the receiver.
wee-ook: This is a whistling type call . This call may grade into a kreek, kik, or a rha. This call is heard when an individual is interfered with an activity. This call is performed by older infants and younger juveniles. This call serves to communicate frustration.
rhork: This is a loud and acoustically complex call emitted by both sexes from older infants to subadult and adult females. This call is heard when the sender receives mild contact aggression. This call serves to communicate low to moderate fear. Mothers will retrieve young who emit this call.
kreek: This call consists of loud screams emitted by both sexes from older infants to subadults and by adult females. This call is heard when the sender receives intense contact aggression. This call serves to communicate moderate to intense fear.
wa: This call consists of loud, high pitched screams emitted by both sexes from older infants to older juveniles . This call is heard when the sender receives contact aggression in severe fights. This call serves to communicate very intense fear and this will elicit other conspecifics to join in the encounter.
kik: This call occurs in a series or as one note . This call has a duration that ranges from 21 to 75 milliseconds. This call is heard in situations when a playful individual is attacked, and this call is emitted by both sexes from older infant to younger juveniles. This call serves to communicate a mixed emotion of fear and play.
rha: This call is described as being loud and noisy and is emitted by both sexes from older juveniles on up. This call is seen in situations of a confident attack and as in a defensive threat. This call serves to communicate aggression.
purr: This call sounds like the purring noise made from the domestic cat. This call is heard in situations of conspecific and interspecific contact and approach and is performed by both sexes from older infants on up.
hiss: This call is very low amplitude in nature. This call is heard in situations of play and play mixed with aggressive motor elements and is emitted by males from older juveniles on up. This call functions to decrease avoidance on the part of conspecifics.
keh: This call is low amplitude in nature and is produced by exhalation. This call can grade into a kik call. This call is heard in situations of play and is performed by both sexes from older infants on up. This call functions to decrease avoidance on the part of conspecifics.
genital sniffing: This is when one Red Uakari bends down and sniffs the genitalia of another. This behavioural pattern is used in greeting. This is also seen in pre- and post- copulatory situations, and this behaviour is performed by males from older juveniles on upward.
anal rubbing: This is when an individual will rub the anal region on to a substrate . This behaviour is performed by the adult female and is seen during estrus. This behaviour functions to communicate the sexual condition of the female to males.
urine wash: This is where adult males will vigorously spread urine on themselves. The urine is described as having a sweet, aromatic smell. This behaviour is seen in intimidation displays and functions to communicate aggression.
eyes closed: This is where an individual will reveal the white eyelids . This behaviour is performed by both sexes of all ages and is a common behaviour. This serves to communicate the resting state of an individual.
scalp retraction: This is when the scalp is drawn back and is emphasized by the gray crown hair . This is seen performed by young infants towards juveniles and when a more dominant individual approaches . This is thought to function ease acceptance of contact by an immature towards an adult.
mouth corner retraction, full lip retraction, grin: This is described as a graded series, with the teeth fully or partially exposed . This behaviour is performed by infants and juveniles. This is seen when individuals approach or have contact with individuals that are more dominant than they are . This display functions as an appeasement during low agonistic situations and as a contact maintaining behaviour during affiliative situations.
protruded lips: This is where the lips are hyperextended into a pucker . This behaviour is performed by juveniles and adult females and occurs in food solicitation and in situations of when one individual does not want to groom another. During social grooming the prospective groomer will move away when given this behaviour.
lip smack squint: This is where the scalp is protracted (pushed down) and the mouth is opened and closed . This behaviour is seen when an individual is approached by a more dominant individual. This behaviour is performed by both sexes from age juvenile and up. This behaviour functions as an appeasement signal.
open mouth threat: This is where the mouth is open and the face is in a tense position . This behaviour is performed by both sexes from the age of juvenile on u . This behaviour functions to signal aggression.
play face: This is where the mouth is opened and face is in a relaxed position . This behaviour occurs during social play and is performed by both sexes from the age of juvenile on up. This behaviour functions to signal playfulness on the part of the sender.
scalp retraction with protruded lips: This display is when an individual gives scalp retraction and protruded lips at the same time . This is given when an individual is startled. This display is seen given by infants and juveniles of both sexes and by adult females. This is used to communicate pain and/or fear, and when this is given by infants, the mothers will retrieve them .
scalp retraction with mouth corner retraction or grin: This is when an individual gives scalp retraction with the corners of the mouth pulled back or a grin . This is seen when an individual is approached and contacted by an individual that is more dominant . This display is performed by older infants and juveniles of both sexes and by adult females. This is described as to communicate "conflict between approach and avoidance in potentially agonistic settings".
tail wagging: This is when an individual will wag the tail from side-to-side . This display is seen after squabbles and at the end of grooming. This display is performed by both sexes of older infants on up . This communicates general arousal on the part of the sender.
allogrooming solicitation: This is when an individual will sit erect and then will look up and/or away . This display is seen between individuals that have social grooming for a long period of time . This behaviour is seen by older juveniles of both sexes, subadult males, and adult females . The individual this display is directed to will respond with grooming.
single leg jerk: This behaviour is described as a "unilateral, abrupt leg extension- flexion". This is performed by adult males when they are mildly annoyed or disturbed. This serves to communicate aggression.
hindquarters bounce: This is like single leg jerk except for that it is bilateral . This is performed by adult males when they are mildly annoyed or disturbed. This serves to communicate aggression .
branch slapping and arm raising: This is when an individual will raise the arms and/or then bring them down hard on a branch . This is performed by adult males when they are mildly annoyed or disturbed. This serves to communicate aggression.
quadrupedal stand and stare: This is when an adult male will stand up and stare at an individual that is causing him annoyance . This display is seen in situations when adult males are moderately annoyed or disturbed. This behaviour serves to communicate aggression.
strut: This is when an adult male will move quadrupedally forward with the knees and elbows in a rigid fashion . This display is seen when adult males are moderately to strongly annoyed or disturbed. This behaviour serves to communicate aggression.
branch rocking: This is when an adult male will sway from side-to-side while up in the trees . This display is seen when adult males are moderately to strongly annoyed or disturbed. This behaviour serves to communicate aggression.
look away: This is when an individual will avoid eye contact with conspecifics . This behaviour is performed by both sexes from subadult on up, and this occurs when the stimulus is persistently staring at the individual. The stimulus will respond with mutual avoidance of eye contact.
leg extension: This is when an individual will extend the hind leg on one side of the body. This is performed by both sexes from older juveniles on up, and this display is seen in situations of mild annoyance. This behaviour serves to communicate low-level aggression.
arched back: This is when an individual will raise the back and form a strong curvature with the back . This behaviour is seen in situations where there is a sudden stimulus, in an attack, as a defensive threat, and by females during copulation. This behaviour is performed by both sexes from older juveniles on up, and for the female this is used as a sexual presentation behaviour towards her mate . This behaviour serves to communicate fear and/or aggression or sexual readiness in the case of a female in estrus. This display makes the individual look larger .
piloerection: This is when an individual will piloerect the pelage of the dorsum and external limb surfaces . This display is seen during attacks of both conspecifics and different species, loud noises, and as a defensive threat posture. This behaviour is performed by both sexes from older juveniles on up. This display serves to communicate moderate to intense fear and aggression. This behaviour makes the individual look larger.
branch shaking: This is when an individual will briefly and vigorously shake branches. This is seen when allogrooming solicitation is ignored, or when social grooming is disrupted. This behaviour is performed by both sexes in both subadult and adult stages. This display serves to communicate aggression .
social grooming: When one individual will groom another, usually removing dead skin and parasites. This is used to reinforce social bonds amongst members of a group. The Red Uakari engages in a high rate of social grooming, with adults females performing this behaviour more often than adult males or juveniles. Adult females with young will usually direct social grooming towards them more than other individuals. Grooming tends to be reciprocal, and if one individual does not reciprocate, the grooming bout is ended.
contact aggression: This is a graded behaviour that varies from pushing to biting . This behaviour is seen in disputes with conspecifics and with different species and is performed by both sexes from young juveniles on upward. This serves to communicate aggression.
The Red Uakari gives birth to a single offspring. There are no external signs of estrus in female Red Uakaris. This Uakari gives birth at night . In
The ritual of copulation begins with the male sniffing and/or licking the genitalia of the female . If the female is non-receptive, she will try to escape or engage in aggressive behaviour with the male . Receptive females will sometimes rub the anogenital region on branches . Receptive females will stand quadrupedally with the hindquarters facing the male with the tail raised . Males will approach the female, sniffing while he approaches. The male will mount the female with the thighs abducted and flexed . Copulation last five minutes with multiple intromissions separated by pauses, and both the male and female will make pelvic thrusts during copulation. After copulation the male will sniff the female's genitalia and engage in social grooming. Copulation can occur at intervals of one-half hour to several hours when the female is receptive. During the time the female is receptive she may mate with the same male or different males.
Did you know?
Uakari’s are the only short-tailed American monkeys.
Uakaris Groups average 10-30 and can reach 100. Troops sleep together but split up during the day to forage in smaller groups. A group contains several males and females, and all members help to look after the young. Females give birth only once every 2 years. Their natural predators are birds of prey, but humans are the most dangerous.
Uakaris are listed as CITES 1. They are hunted for their meat and for the pet trade and are now very rare. They are found in a small area and they do not breed rapidly. They are also threatened by logging of their forest habitat.