Golden-headed lion tamarin
Leontopithecus chrysomelas

SOCIAL ORGANIZATION AND BEHAVIOR

Wild golden-headed lion tamarins live in groups of about five individuals, excluding infants, and have been documented in the wild in groups as large as nine (Dietz et al. 1996). One or two adults of both sexes are usually present in the group, but there are usually more adult males than females. If there are two adult females within the group, only one is reproductively active. Also within the group are the offspring of various ages from two to three litters of the reproductive female (Dietz et al. 1994; Raboy 2002; Raboy & Dietz 2004). No genetic tests have been done to analyze paternity in groups of wild tamarins and it is unknown if the female breeds with more than one adult male. The younger group members remain in the group as they mature, sacrificing their own reproductive opportunities, and helping to raise their younger siblings in a system known as cooperative breeding. There is very little published information about dispersal rates of young males and females in the wild, but the documented pattern is that as non-reproductive adults, males and females disperse from their natal groups to avoid breeding with one of their parents and look for another group to join and in which to reproduce (Dietz et al. 1996; Raboy 2002). Golden-headed lion tamarins leave their natal groups between nine and 47 months of age and the average age of dispersal is 26.8 months, but may be closer to 38.7 months (Raboy 2002). Both males and females leave their natal groups in order to gain access to breeding opportunities, but if breeding vacancies appear within the group in which they were born and the opposite-sex parent disappears or transfers, males or females may inherit a position within their natal group (Raboy 2002). In other cases, young golden-headed lion tamarins may time transfers for when breeding vacancies are available in neighboring groups. One way the monkeys assess this is during intergroup encounters (Raboy 2002). Fluctuating between periods of stability and periods of rapid change, golden-headed lion tamarin groups remain stable for two to almost five years with no dispersal or immigration (Raboy & Dietz 1996). During periods of stability, the only increase in group size is due to new births. Turnover periods, occurring every few years, are marked by high rates of disappearance and immigration in which young golden-headed lion tamarins leave their natal groups to join another group or form their own group with a member of the opposite sex. Adult golden-headed lion tamarins may transfer between groups more than once, and changes in group composition may also be due to secondary transfer of adults (Raboy 2002). Smaller and newly formed groups are much more likely to accept immigrants; females enter groups without a resident breeding female while males enter a group with a breeding vacancy, aggressively displace breeding males, or enter a group and assume a non-breeding position (Raboy & Dietz 1996).

Some information about social behaviors must be extrapolated from studies of captive golden lion tamarins (L. rosalia) simply because there is not enough data from wild or captive studies on golden-headed lion tamarins. Though the two species are closely related and likely share a repertoire of similar behaviors, using data from golden lion tamarins should be done prudently as new research on golden-headed lion tamarins will likely reveal similarities and differences between the species. Among golden lion tamarins, grooming is a major form of social activity and occurs between all family members either as they huddle in close contact during the day or evening or between pairs of individuals throughout the day (Kleiman et al. 1988). Adult females groom males more frequently than the reverse, and this may indicate that adult males are dominant over adult females within the group. Juveniles and subadults have high frequencies of grooming neonatal infants as they are interested in the youngest group members and attempt to make contact with them as often as possible. They will also groom the infants' mother in an attempt to get closer to the newborn (Kleiman et al. 1988).

Because of their relatively large home range sizes, golden-headed lion tamarins encounter other groups less frequently than golden lion tamarins, but when they do, they exhibit territorial behavior. Intergroup behavior is aggressive and includes bouts of vocalizing, chasing, and fighting between individuals (Dietz et al. 1996; Raboy & Dietz 2004).

REPRODUCTION

The social structure of golden-lion tamarins indicates they employ a monogamous mating system, but the presence of non-reproductive adult males and females indicates that the mating system is flexible and may also change over time depending on a number of factors that have not yet been tested (De Vleeschouwer et al. 2000). Furthermore, while it is thought that only one adult female per group breeds and she suppresses reproductive behavior in other females in the group through aggression and other mechanisms, no genetic tests have been done on wild golden-headed lion tamarins to confirm genetic relatedness of the young and other group members (De Vleeschouwer et al. 2001). Very few reports of polygynous groups of golden-headed lion tamarins have been published, but there are more instances documented in captive than in wild animals. When a second female does breed, she is often not successful in raising her infants. Captive studies have revealed that she either gives birth to stillborn infants or if they are live, the infants are often targeted by severe aggression from the dominant breeding female and they may be killed (Diego & Ferrari 1996; De Vleeschouwer et al. 2001). Some theories about what may lead to the tolerance of a second breeding female in some groups and not others include the presence of an unrelated male, a large number of helpers, or a relative richness in important food resources (De Vleeschouwer et al. 2001). It is in the dominant breeding female's interest to limit the number of infants in the group at one time through reproductive suppression because caregivers are vitally important to the survival of infants, and she may not want her mate to spend time caring for another female's infants, or, because pregnancy and lactation are such energetically taxing feats, resources are not abundant enough to support more than one lactating female (De Vleeschouwer et al. 2001).

In the wild, females can reproduce for the first time before two years of age, but given the small sample size of females of known age, it is difficult to conclude if this is normal as other females first gave birth after 2.5 years (Raboy 2002). Young females reach puberty at age 16 months and non-reproductive, sexually mature females exhibit normal ovarian cycles, which last about 21 days, even though they do not reproduce within their groups (French et al. 2002). One component of this reproductive suppression is the behavior of the reproductive female in the group that can include aggressive interactions such as biting, hitting, or pushing or can be more indirect and involve sending chemical cues by scent marking surfaces (Chaoui & Hasler-Gallusser 1999). Young males are also somewhat reproductively suppressed, though they are much less frequently studied than females. In captivity, if they remain in their natal group, male golden-headed lion tamarins do not reach sexual maturity until 28 months, but if they are removed from a group containing their mother and sisters, they will reach sexual maturity at 17 months (Chaoui & Hasler-Gallusser 1999). One explanation for this pattern of development could be that it is an adaptation against inbreeding; to avoid mating with his close relatives, a young male that does not immigrate into a new group is reproductively inhibited but if he leaves his natal group, he becomes sexually mature and may assume a breeding position in his new group.

There are no external signs of ovulation, therefore reproductive females attract attention from breeding males by presenting their rumps toward the male and slightly lifting the tail. The male responds to this behavior by inspecting and sniffing the female's genitals, evaluating her attractiveness and reproductive status (De Vleeschouwer et al. 2000). The highest occurrence of sexual behavior is during the peak of female receptivity, and once a female conceives, gestation lasts about four months (129 days) (French et al. 2002). Golden-headed lion tamarins exhibit birth seasonality even though they live in an area in which resources are equally abundant year-round. Most births occur from October through April and there is a significant absence of births from May to September (Bach et al. 2001). Most primates that exhibit birth seasonality do so because reproductive events are energetically expensive, and to maximize likelihood of infant survival, breeding, birth, and lactation occur during times of high resource abundance (Sussman 2000). Golden-headed lion tamarins seem to exhibit birth seasonality in accordance with photoperiod. This may be an adaptation because there may be behavioral advantages of raising offspring during longer days (Bach et al. 2001). In captivity, golden-headed lion tamarins can have one or two litters per year but in the wild they usually only have one per year (De Vleeschouwer et al. 2001). Rates of twinning are similar in captivity and in the wild, with more than half of the births resulting in twins rather than singletons (Bach et al. 2001).

PARENTAL CARE

Cooperative infant care, in which almost all group members in addition to the mother care for infants by transporting them, playing with them, and even provisioning them with solid food, is a hallmark of callitrichine social systems (Tardif et al. 2002). Golden-headed lion tamarin infants are born weighing close to 10% of the mother's total body weight and if there are two, the twins can be an enormous burden for the mother to bear as they both need to be carried, nursed, and protected from predators (Van Elsacker et al. 1992). Other group members, including the presumable father of the infants as well as the older siblings spend time carrying and socializing with them, greatly contributing to their survival (Sussman 2000). One of the reasons they do this is because of their relationship with the infants: the father has an interest in ensuring the infants will live to reproduce and increase his own fitness, while the older siblings get experience caring for infants, which will help when they have offspring of their own, and they improve their fitness through kin selection (Sussman 2000). Though a new golden-headed lion tamarin mother has helpers on which to depend, she is the only one to carry her infants for the first two days, rebuffing all advances from group members to inspect and take the infants (de Oliveira et al. 1999). On the third day, the mother will allow the presumable father to carry the infant and by the fifth day, any other helpers can begin to transport the infant. Among lion tamarins, the amount the infant is carried decreases as it grows: by the age of four weeks, about 15% of the time is spent off of a carrier, though always nearby at least one group member for safety, and at seven weeks, they are still only spending about 20% of their time off the carrier. By 10 weeks, an infant is only being carried about half of the time (Tardif et al. 2002).

Another important behavior of cooperative infant care is food provisioning. For the first four weeks, the infants exclusively nurse, but food sharing begins during week five (Tardif et al. 2002). By week 12, young golden-headed lion tamarins are being provisioned at the highest rates, and sharing will decrease over time such that by about five months of age, they are no longer being provisioned by group members (Tardif et al. 2002). Though there is no data from wild golden-headed lion tamarins, wild golden lion tamarin juveniles (L. rosalia) are provisioned until 21 months of age, and the pattern may be similar across species (Tardif et al. 2002). Sharing food with infants may teach them an appropriate diet and provide them with important nutrients. In younger infants, foods that are high in lipids and protein that they are unable to acquire on their own, such as insects, are shared more frequently than other types of foods. Older juveniles receive a wider variety of foods, probably as a way to learn about appropriate foods (Tardif et al. 2002).

COMMUNICATION

Both vocal and chemical communication are important to golden-headed lion tamarin groups. Because they live in tropical forests, visual communication is less important in long-distance interactions but is important in interactions between individuals that are in proximity (Ruiz-Miranda & Kleiman 2002). The only available information about vocal and visual communication in lion tamarins is for the golden lion tamarin (L. rosalia), but it is believed that similarities exist among all species of Leontopithecus (Ruiz-Miranda & Kleiman 2002). There are six discrete categories of vocalizations in golden lion tamarin communication: tonal, clucks, trills, atonal, multisyllable, and combination (Ruiz-Miranda & Kleiman 2002). Tonal vocalizations include the "whine" and "peep" calls and serve as alarm and affiliation calls. "Whines" are given in reaction to the presence of predators while "peeps" are sounded by solitary young after being reunited with the group or by any group member upon finding food (Kleiman et al. 1988; Boinski et al. 1994; Ruiz-Miranda & Kleiman 2002). "Clucks" signal reaction to the presence of a novel item or are giving during foraging bouts. They also can signal aggression when golden lion tamarins encounter neighbors or intruders and are given while chasing or mobbing predators (Kleiman et al. 1988; Boinski et al. 1994). "Trills" have multiple purposes but mainly serve to indicate the location of the caller to other individuals over long distances. Atonal calls such as "rasps" or "screeches" are heard mostly during playing or as playing escalates to fighting (Kleiman et al. 1988; Boinski et al. 1994). Multisyllable calls include the most important vocalizations for group cohesion, the "short" and "long calls." These are typically heard as golden lion tamarins leave their sleeping sites in the morning to locate their neighbors and are heard throughout the day as individuals keep in vocal contact with other group members (Peres 1991; Ruiz-Miranda & Kleiman 2002). Combination calls also serve multiple purposes and include "trill-rasps," "trill-whines," and "cluck-whines." These are used by juveniles begging for attention, protection, or food or by group members as they defend their territory against intruders or predators (Ruiz-Miranda & Kleiman 2002).

Both male and female golden-headed lion tamarins have well-developed scent glands on their chest and around their genitals which secrete chemicals used to communicate information about the individual including sex and reproductive status as well as territory demarcation. Unfortunately, no work has been done to analyze the chemical composition of these secretions and therefore little information is understood about the mechanism by which these work to signal other golden-headed lion tamarins (Ruiz-Miranda & Kleiman 2002).

Information about visual communication in golden-headed lion tamarins in also limited and therefore what is known about visual signals in golden lion tamarins must be applied to the former species (Ruiz-Miranda & Kleiman 2002). The repertoire of visual signals is limited compared to the other communication forms, but includes both postural and facial expressions that act as signals to nearby individuals (Kleiman et al. 1988; Kinzey 1997). Golden lion tamarins exhibit tongue-flicking, arch-walking, tail thrashing, rump displays and piloerection in sexual and social contexts (Kinzey 1997; Ruiz-Miranda & Kleiman 2002). Most visual signals are used during territorial encounters, social interactions, and reproductive events (Ruiz-Miranda & Kleiman 2002).

Content last modified: July 20, 2005

Written by Kristina Cawthon Lang. Reviewed by Becky Raboy.

Cite this page as:
Cawthon Lang KA. 2005 July 20. Primate Factsheets: Golden-headed lion tamarin (Leontopithecus chrysomelas) Behavior. <http://pin.primate.wisc.edu/factsheets/entry/golden-headed_lion_tamarin/behav>. Accessed 2008 July 4.