SOCIAL ORGANIZATION AND BEHAVIOR
Bearded sakis live in relatively large multi-male groups (several adult
males, females, and offspring) with group size averages ranging between 2.3 and
32.7 individuals. Single groups have been seen numbering as high as 44 or more
individuals (Vessey et al. 1976; Roosmalen et al. 1981; Branch 1983; Ayres 1989;
Ferrari 1995; Norconk 1996; Bobadilla & Ferrari 1998; Ferrari et al. 1999;
Norconk et al. 2003; Veiga 2005; Silva & Ferrari 2009). However, groups
usually have between around 10 and 30 members (Roosmalen et al. 1981;
Mittermeier & van Roosmalen 1981; Johns & Ayres 1987).
The social system of bearded sakis has been described as a complex
fission-fusion system (Veiga 2005; Silva & Ferrari 2009). While foraging,
bearded saki groups travel together between feeding trees, and then spread out
into smaller subgroups between 50 (164.0 ft) and a couple hundred meters from
each other while feeding (van Roosmalen et al. 1981; Ayres 1989; Kinzey &
Cunningham 1994; Norconk & Kinzey 1994; Silva & Ferrari 2009).
Subgroups are commonly an adult mated pair and offspring, and individual males
may associate in subgroups preferentially with certain females (Peetz 2001;
Silva & Ferrari 2009). When the group is spread out foraging however, the
members are in constant vocal contact (Peetz 2001). Larger subgroups have been
known to last for several days (Silva & Ferrari 2009).
Photo: Luiz Claudio Marigo
In one study, a single group of C. satanas had a variety of social
behaviors, including social rest (36.6% of social activities), alarm
vocalizations (25.2%), play (7.8%), lining up (7.0%), agonism (4.4%) and
suckling (1.7%), copulation (1.7%), mounting (1.7%), and leaf shaking (1.7%)
(Silva & Ferrari 2009). During social rest, the group or subgroup comes
together within 2 meters. As they line up several males come together and rub
their bodies together while sitting next to each-other side-by side (Peetz 2001;
Silva & Ferrari 2009). This activity is of short duration but occurs often
during threatening situations (Araya & Peetz 2000; Silva & Ferrari
2009). When neighboring groups come into contact with one other near the
periphery of their home ranges, intergroup interactions may occur involving
males vocalizing and staring at each other (Silva & Ferrari 2009).
Allogrooming, when it does occur, is often between adult males (Silva &
In one wild group, the older male appeared to hold a position of importance,
intervening in agonistic interactions, as well as deciding where the group
traveled and participating in most hugging and lining-up events (Peetz 2001).
Generally, agonism is rare in the wild (Peetz 2001). Agonistic behaviors
have been studied in captive bearded sakis (C. utahicki) however.
Categories of such behaviors include threatening, snatching, bounding,
balancing, and chasing (Fernandes 1993). Tail-wagging increases when the
situation is stressful, excited, or tense (Fernandes 1993).
In general, there are limited data on reproduction and some disagreement
about how to define the mating system of bearded sakis. Some authors postulate a polygynous
system, while others argue that it may be closer to a multi-male/multi-female
system (Peetz 2001). The majority of copulations last around one minute (40-90
seconds) with those involved returning to their previous activities soon after
Photo: Luiz Claudio Marigo
In the wild in Venezuela, births occur during the dry season (December-April)
while in Suriname, births occur at the beginning of the rainy season
(December-January) (van Roosmalen et al. 1981; Peetz 2001). In captivity, no
birth season is seen (Malacco & Fernandes 1989). Females exist sexual
swellings in which the ano-genital region becomes bright red (van Roosmalen et
al. 1981; Peetz 2001). Presenting in captivity consists of a female lying down
in front of a male and moving the tail away from the ano-genital region, while
in the wild, no such behaviors were noted (van Roosmalen et al. 1981; Peetz
2001). There is anecdotal evidence that a female may copulate with several
males in a row in the wild (Silva & Ferrari 2009).
Gestation is around 5 months (van Roosmalen et al. 1981; Kinzey 1997).
In general, there is little information about infant growth and development
in bearded sakis. Most data comes from a single study of wild C.
chiropotes in Venezuela and a single C. albinasus and C.
chiropotes hybrid infant in captivity (Hick 1968b cited in van Roosmalen et
al. 1981; Peetz 2001). Infant bearded sakis are born as singletons with their
eyes open (van Roosmalen et al. 1981; Malacco & Fernandes 1989; Peetz 2001).
The interbirth interval is probably normally no less than two years (Peetz
2001). In the first several weeks of life, the infant does little but sleep
(Hick 1968b in van Roosmalen et al. 1981). For the first two months, the infant
is carried ventrally, moving to mostly dorsal carriage in the third month. By
month three, the infant will move up to a meter away from its mother, and start
moving and playing on its own. Independent travel and the eating of solid foods
start in the 4th month and social play increases during this time. By the 5th
month, the infant is still carried while the group is traveling but may move up
to 10 meters away from its mother and it feeds independently more often. In the
6th month, the infant is often pushed off the mother, and only carried during
long-distance travel. The infant is also seen more than 10 meters from its
mother. In the 7th-9th months, independent travel increases as does independent
feeding, and by the 10th month of life, travel is almost entirely independent.
From the 10th-13th month, the mother is still followed and food is taken from
her. Maturation begins around three years of age (Peetz 2001).
Even less is known about communication in bearded sakis, and in most cases
data are limited to anecdotal observations. A high-pitched whistling
vocalization is typically emitted during travel, foraging and as a contact call
(Ayres 1981 cited in Ayres 1989; van Roosmalen et al. 1981). Low pitched calls
are given during feeding and resting (Ayres 1989). Weak chirps indicate
satisfaction and shrill cries are heard when disturbed (Hick 1968a). Loud
squeaks are emitted when predators are spotted (Peetz 2001). Vocalization is
also often heard in times of excitement (Peetz 2001).
Visual signals of anger include rearing on the hindlimbs, vibrating the beard
and grinding the teeth (Hick 1968a). Tail-wagging also occurs when bearded
sakis are excited, but probably does not have an efficient communicatory
function (Fernandes 1993).
Content last modified: June 26, 2009
Written by Kurt Gron. Reviewed by Sarah Boyle.
Cite this page as:
Gron KJ. 2009 June 26. Primate Factsheets: Bearded saki (Chiropotes) Behavior . <http://pin.primate.wisc.edu/factsheets/entry/bearded_saki/behav>. Accessed 2014 March 11.