SOCIAL ORGANIZATION AND BEHAVIOR
In general, woolly monkey social groups are large, averaging 44-49
(L. cana), 24-43 (L. lagotricha), 21 (L.
lugens), 23 (L. poeppigii) individuals (reviewed in Di
Fiore & Campbell 2007). However, groups can be larger. For
example, L. cana groups of at least 62 individuals are known to
exist (Peres 1996). Reproducing adults of both sexes are present in the
social group (reviewed in Di Fiore & Campbell 2007).
Photo: Noga Shanee
Woolly monkey social groupings are very flexible (Di Fiore &
Strier 2004). Their social system is best classified as
multimale-multifemale (Di Fiore & Rodman 2001; Di Fiore 2004).
Woolly monkey groups are typically found spread out in the forest, often
found over several acres, but in contact through vocalizations
(Nishimura 1994; Peres 1996; Di Fiore & Campbell 2007). Groups are
found as a single spread out unit, in more coherent feeding groups, or
may temporarily split into several "subgroups" (Ramirez 1988; Peres
1996; review in Di Fiore & Campbell 2007). However, most of the
time woolly monkey groups can be considered as a single cohesive unit
(Di Fiore & Campbell 2007). "Subgroups" do not normally move
independent of each other. They usually move in a coordinated fashion
and in contact through vocalizations, although occasionally they will
split off for days at a time (Peres 1996; Di Fiore & Campbell 2007).
Non-group individuals may "visit" other groups and temporary
associations of more than one group are known (Nishimura 2003; Di Fiore
& Campbell 2007; Di Fiore et al. 2009).
Grooming bouts in L. poeppigii last less than 5 minutes,
and adult males are the most common recipients of grooming (Di Fiore
& Fleischer 2005). Agonism involves displacements, threat displays,
lunges, chases, or physical contact (Di Fiore & Fleischer 2005).
Aggression and physical confrontation between males (L.
lagotricha & L. poeppigii) occurs only rarely
(Nishimura 1994; Di Fiore & Fleischer 2005). Female-female
aggression is common (Di Fiore & Fleischer 2005). In fact, males
(L. lagotricha & L. poeppigii) are not often found
in close proximity to other males, and particularly avoid one another
while feeding (Nishimura 1994; Stevenson 1998; Nishimura 1997; Di Fiore
& Fleischer 2005). However, neither sex feeds alone, and both are
often found feeding with other females (Nishimura 1997). Males are
dominant over others in the group, and larger males are dominant over
smaller individuals (Nishimura 1994; Di Fiore & Fleischer 2005).
Affiliative behavior (L. lagotricha) is rare except between
mothers and their young offspring (Nishimura 1994). Non-infantile
suckling occurs in L. lagotricha, where nursing females will
suckle adult males (Nishimura 1994). Playing is common, and includes
chasing, wrestling, grasping, pulling, pushing and biting (Nishimura
There is some variation among the woolly monkeys in dispersal
patterns (Di Fiore & Fleischer 2005). Females disperse in L.
lagotricha (Nishimura 1994; review in Di Fiore & Campbell
2007). However, molecular evidence (L. poeppigii) indicates
that both sexes disperse (Di Fiore & Fleischer 2005). Males are
more philopatric than females although occasionally observed solitary
males and bachelor groups indicate that male dispersal does occur (Di
Fiore & Fleischer 2005; Di Fiore & Campbell 2007; Di Fiore et
al. 2009). Wild L. lagotricha females disperse at an age of
around 6 years old and may associate with other groups for short periods
before settling on a new group (Nishimura 1990b; 2003).
Mating in woolly monkeys is polygamous (Ramirez 1988). Females
first give birth at an average age of 9 years and males are adult sized
at 8 years old (Ramirez 1988; Nishimura 2003). Prior to copulation,
females typically solicit males (L. poeppigii) (Di Fiore &
Fleischer 2005). Solicitation consists of a female shaking her head
with an open-mouthed grin toward a male who may reciprocate (Di Fiore
& Fleischer 2005). Another behavior associated with copulation is
the so-called "tooth-chatter" or "click" where both female and male
woolly monkeys retract their lips and open and close their mouth
(Nishimura 1988; 2003). Females also use this type of behavior to show
receptivity and to solicit copulation (Nishimura 1990a).
There are no external signs of female estrus or receptivity
(Nishimura 1990a). Copulation is dorso-ventral, with the female
typically lying on her ventrum and is single mount (Nishimura 1988).
Mating lasts around five minutes and occurs year-round (L.
lagotricha & L. poeppigii) (Nishimura 1988; Di Fiore
& Fleischer 2005). Females sometimes harass copulating pairs by
standing nearby, baring their teeth, bouncing, and branch-shaking, often
interrupting the copulating pair. Males generally do not harass in the
same way (Di Fiore & Fleischer 2005). Female-female mate competition
may be quite high, with up to one-fifth of copulations subjected to
harassment from other females (Di Fiore & Fleischer 2005). Females
will copulate with multiple males within the group, including subadults
(Di Fiore & Fleischer 2005).
The average interbirth interval in L. lagotricha is around
three years and females are sexually inactive for two years following
the birth of an infant (Nishimura 2003). However, copulation may occur
while females are pregnant (Nishimura 2003). While copulation occurs
year round, there are seasonal patterns of births (Nishimura 2003). For
example, at the Macarena-Tinigua National Park in Colombia, all births
fall between July and December corresponding to the late wet season and
early dry season (Nishimura 2003). Mating experiences peaks in
frequency (at Macarena-Tinigua this is between December and May) that
result in a birth season (Nishimura 1992; 2003).
Gestation in L. lagotricha is between 7 and 7.5 months
(Williams 1967; Mack & Kafka 1978; Nishimura 2003). The
reproductive cycle of L. lagotricha is 21.3 days (Begehold
& Vermeer 2009).
Neonatal L. lagotricha males weigh on average 510 g (18.0
oz) and females weigh an average of 432 g (15.2 oz) (Smith & Leigh
1998). The eyes are open at birth and infants are lighter in color
than adults (Williams 1967; Kavanagh & Dresdale 1975). Neonates are
carried ventrally in the first or first several weeks of life, moving to
the mother's back afterwards (Kavanagh & Dresdale 1975; Mack &
Kafka 1978). For the first several weeks of life, an adult male will
attend to a mother and her infant, gradually ceasing doing so (Defler
In captivity, L. lagotricha infant mortality is 8.3% in the
first year for live births, and 20.4% births are stillborn (Mooney &
In captivity, by the sixth to eighth week of life, the infant begins
to move away and off of the mother and by six months old, most travel is
independent (Mack & Kafka 1978; review in Ramirez 1988). Items are
first grasped in the fifth week of life and mouthing of objects starts
in the seventh week of life (Mack & Kafka 1978). First solid foods
are tried in the first several weeks after birth, and infants are weaned
around six months of age (Defler 2004).
There are three types of vocalizations emitted by wild L.
lagotricha: contact calls, alarm calls, and social interaction
calls (Stevenson 1997). Contact calls are divided into two types:
long-distance and medium distance calls. Two types of alarm calls are
distinguished, with barking indicating predators and mild barking
indicating possible, but unconfirmed threats. Social calls include
agonistic, play, and grooming vocalizations. Common agonistic calls
include shrieking (heard from individuals who are being attacked) and
whining (emitted by juveniles being rejected by their mothers)
Woolly monkeys perform two types of scent-marking: chest-rubbing and
anogenital rubbing (Di Fiore et al. 2006). Chest-rubbing is performed
by wetting a surface with saliva and then rubbing the chest on it.
Anogenital rubbing consists of the woolly monkey pulling its anogenital
region along a branch while seated (Defler 2004). Chest-rubbing in
captive L. lagotricha may have reproductive as well as spacing
functions (White et al. 2000). In the wild, scent-marking communicates
male quality or ability as well as possible reproductive functions (Di
Fiore et al. 2006).
Some types of visual communication used by woolly monkeys include
head shaking, hand tuffs, branch shaking displays, and teeth chattering
(Defler 2004). Stressful situations sometimes cause penile erection in
male woolly monkeys (Nishimura 1990b).
Content last modified: September 30, 2010
Written by Kurt Gron.
Cite this page as:
Gron KJ. 2010 September 30. Primate Factsheets: Woolly monkey (Lagothrix) Behavior . <http://pin.primate.wisc.edu/factsheets/entry/woolly_monkey/behav>. Accessed 2015 January 29.