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Woolly monkey


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).

L. poeppigii
L. peoppigii
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 1990a; 1990b).

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 2004).

In captivity, L. lagotricha infant mortality is 8.3% in the first year for live births, and 20.4% births are stillborn (Mooney & Lee 1999).

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) (Stevenson 1997).

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 . <>. Accessed 2020 July 6.