All-male Groups Research Articles

Association between C-reactive protein and cognitive deficits in elderly men and women: a meta-analysis

Certain risk factors for cognitive decline appear modifiable. A potentially modifiable marker of inflammation, C-reactive protein may be associated with cognitive deficits, although not all studies have found a relationship between C-reactive protein and cognitive ability. Further, few research papers have examined whether gender may affect any association between C-reactive protein and cognitive deficit. To better understand the association between C-reactive protein, cognitive deficit, and gender in elderly people, we meta-analyzed cross-sectional studies that reported cognitive ability assessed by the Mini-Mental State Examination or an equivalent measure, C-reactive protein concentrations, and gender. While we identified no studies containing only male subjects, the two identified studies containing both female and male subjects (n = 2,525) showed an effect size for cognition of -0.1809 (95% confidence interval, -0.2652 to -0.0967, p = 0.000025) between high and low C-reactive-protein groups. In contrast, the two identified studies containing only female subjects (n = 1,754) showed an effect size for cognition of 0.0345 (95% confidence interval, -0.0594 to 0.1285, not significant). In the context of a small number of source studies and lack of an all-male group, these results suggest that any association between C-reactive protein and cognitive deficits may be stronger in elderly men than in elderly women.

Pharmacokinetic Comparison of a New Sustained-Release Formulation of Glimepiride/Metformin 1/500 mg Combination Tablet and a Sustained-Release Formulation of Glimepiride/Metformin 2/500 mg Combination Tablet in Healthy Korean Male Volunteers: A Randomized, 2-Sequence, 2-Period, 2-Treatment Crossover Study

Background The combination of glimepiride and metformin is used for glycemic control in patients with diabetes mellitus. A fixed-dose combination of glimepiride/metformin 2/500 mg slow-release (SR) formulation was developed to improve compliance in polymedicated patients. To accommodate the various dosing regimens of glimepiride, a glimepiride/metformin 1/500 mg SR tablet was also developed. Objective The goal of this study was to compare the pharmacokinetic properties of SR fixed-dose combinations of glimepiride/metformin 2/500 mg and the newly developed glimepiride/metformin 1/500 mg formulation to meet the regulatory requirements for marketing in Korea. Methods An open-label, randomized, 2-treatment, 2-period, 2-sequence crossover study was conducted with healthy male volunteers. Eligible subjects were randomly assigned to receive a single dose of glimepiride/metformin 1/500 mg SR (test) or glimepiride/metformin 2/500 mg SR (reference) followed by a 1-week washout period and then administration of the alternate treatment. Serial blood samples were collected immediately before and after dosing for 30 hours, and plasma concentrations were determined by using LC-MS/MS with validated methods. Adverse events were assessed by subjects' self-report and interviews addressing general health-related issues. Safety profiles were evaluated throughout the study. Results Thirty-three subjects were enrolled (mean [SD] age: 27.9 [4.95] years [range, 21–40 years]). Safety profiles were assessed for all 32 subjects who were administered the study drugs, and pharmacokinetic characteristics were evaluated in the 30 subjects who completed the study. The geometric mean ratios (90% CIs) of test to reference for the dose-normalized C max and AUC 0–last of glimepiride were 0.98 (0.90–1.07) and 1.06 (0.98–1.14), respectively. In the case of metformin, the geometric mean ratios (90% CIs) of test to reference for C max and AUC 0–last were 1.06 (0.98–1.15) and 1.04 (0.97–1.12), respectively. Nine adverse events were reported. Among them, loose stool, abdominal pain, and headache were considered to be likely related to the study drug. All reported adverse events were mild in intensity. Conclusions Dose-proportional characteristics of glimepiride and comparable pharmacokinetic properties of metformin were observed between the SR fixed-dose combinations of glimepiride/metformin 1/500 mg and 2/500 mg. A single dose of either treatment was well tolerated, and the safety profiles of the 2 treatments were comparable in this small, selected all-male group of healthy Korean volunteers. ClinicalTrials.gov identifier: NCT00934323.

Hierarchical polygyny in multiparous lesser flat-headed bats

How males gain access to mates and the potential for female choice will determine whether polygyny can operate at several levels, from within litters and groups to the wider population. Female lesser flat-headed bats (Tylonycteris pachypus) form maternity groups in bamboo stems. Unusually for bats, they are multiparous, providing the opportunity to test whether multi-level polygyny differs among males depending on whether they roost with females, with males or are solitary. We genotyped 662 individuals from 54 internodes and analysed parentage of 165 litters. Our results revealed 170 sets of paternal twins/triplets, of which 96 were full-sibs and 74 were half-sibs. We found that males captured roosting with females typically sired more offspring overall than did other males and also showed a greater tendency to monopolize paternity within both litters and roosting groups. In comparison, males that sired fewer full-sibs were assigned more maternal half-sibs. These latter individuals, which included solitary males and those from all-male groups, might gain copulations either via roaming with furtive mating or during visits by females. Indeed, female lesser flat-headed bats store sperm, so could benefit from multiple mating to reduce genetic incompatibilities. At the same time, however, we found no evidence of outbreeding. Finally, relatedness and mtDNA analyses revealed that polygyny also operated within matrilineal kin, suggesting a system that might promote social cohesiveness. Future studies of individual movements will help to determine the extent to which mixed paternities in litters, matrilines and groups are driven by male or female behaviour.

Seasonality of group size, feeding, and breeding in wild red‐shanked douc langurs (Lao PDR)

In Asian colobines, small one-male groups (OMG) seem to predominate alongside all-male groups (AMG), while larger multimale groups (MMG) are rare, but are reported for Hanuman langurs and red-shanked douc langurs. Recently, however, it has been speculated that the genus Pygathrix could have multilevel societies based on (1) a theoretical extension of the multilevel societies found in Rhinopithecus to all odd-nosed colobines and (2) first data for black-shanked douc langurs. This assumes bands composed of small OMG with a skewed adult sex ratio. Band size may vary with seasonal food availability resulting in smaller bands when feeding competition is increased. To investigate the social organization of red-shanked douc langurs and potential seasonal influences, we observed 2 unhabituated groups at Hin Namno National Protected Area, Lao PDR from March 2007 to August 2008 for 803 hr. We recorded births and performed group counts and scan sampling of feeding behavior. Most births (79% of N = 15) occurred from June-September, indicating a 4-month peak conception season from November to February. Group size averaged 24.5 individuals (range 17-45) with 2.45 adult males (range 1-4). Although the smaller group remained at a stable size (about 18 individuals), the larger group reduced from about 45 to 25 individuals during the 7-months long lean season, when less than 50% of the feeding time was spent on fruits. This suggests feeding competition as a potential cause of seasonal variation in group size. With 1.9 females per male the skew in adult sex ratio was much lower compared with Rhinopithecus, indicating MMG rather than multilevel societies. However, data on the spacing and interaction patterns between recognized individuals need to be collected and analyzed before the social organization can be determined. Detailed ecological data are furthermore required to investigate the basis for the seasonal changes in group size found.

Ontogeny of mating competence and some sexual characteristics in sexually naïve yearling rams (Ovis aries)

Abstract The aim of this experiment was to contribute to the studies on ontogeny of the development of sexual performance and on semen characteristics in yearling Saint Croix rams. The study population was comprised of 30 sexually naive males maintained and raised together in an all-male group from weaning (2 months) until the start of testing (10 months). These males were individually exposed to an estrous-induced female on 6 occasions, with a gap of 7 days between each exposure. The exposures lasted for either 30 minutes or until the first ejaculation was obtained in a vaginal collection vial. Reaction times from introduction of the estrous female to first ejaculation were longest ( P P ≤ 0.01) during tests 3-6. However, semen characteristics (volume and sperm concentration) did not differ significantly ( P > 0.05) with successive tests ( r 2 = 0.95 and 0.36, respectively). It was concluded that 1 or 2 brief exposures to estrous females (with ejaculations) improve sexual performance but not semen characteristics in sexually naive ram lambs.

Behavioral Responses of Silverback Gorillas (Gorilla gorilla gorilla) to Videos

This study examined the impact of video presentations on the behavior of 4 silverback, western lowland gorillas (Gorilla gorilla gorilla). On each of 5 occasions, gorillas viewed 6 types of videos (blue screen, humans, an all-male or mixed-sex group engaged in low activity, and an all-male or mixed-sex group engaged in agonistic behavior). The study recorded behavioral responses and watching rates. All gorillas preferred dynamic over static videos; 3 watched videos depicting gorillas significantly more than those depicting humans. Among the gorilla videos, the gorillas clearly preferred watching the mixed-sex group engaged in agonistic behavior; yet, this did not lead to an increase in aggression or behavior indicating agitation. Further, habituation to videos depicting gorillas did not occur. This supports the effectiveness of this form of enrichment, particularly for a nonhuman animal needing to be separated temporarily due to illness, shipment quarantine, social restructuring, or exhibit modification.

Association patterns of African elephants in all-male groups: the role of age and genetic relatedness

Strong social bonds are uncommon among male mammals. In many mammals, however, males form all-male groups, providing opportunities for male–male bonds to emerge. We examined association patterns of male African elephants, Loxodonta africana, in all-male groups and assessed the influence of age and genetic relatedness on these associations. We also examined the influence of age and genetic relatedness on the choice of sparring partners in male elephants. Males had many weak and random associations and few valuable relationships. Male associations were positively correlated with genetic relatedness, suggesting that kinship influences patterns of male associations. Male associations were negatively correlated with age disparity, and males were more likely to spar with other males closer in age to themselves. These results suggest that males associate with other males of similar age in part because sparring may facilitate the development and maintenance of motor and psychological responses to sudden and unexpected events that occur during play; this may help prepare males for male–male competition. We also found that older males had high centrality and strength in social networks, suggesting that older males influence the cohesion of male social groups. Consequently, the elimination of older males from elephant populations by poachers or trophy hunters could negatively affect social cohesion in male elephant groups. Finally, we found that age and genetic relatedness were not significantly correlated, suggesting that male associations based on age and relatedness did not overlap. These findings highlight the complexity of male social relationships in all-male groups.

Considerations in Coaching Girls and Women in Sport and Physical Activity Settings

The number of girls and women involved in sport has risen dramatically over the last several decades. Given this increase, an interesting question is whether or not there are important differences in coaching girls as compared to coaching boys. A search for coaching books published since 1980 with titles suggesting a discussion of gender differences in coaching results in one book focusing on coaching boys and over 30 books that focus on coaching girls. The books that focus on coaching girls include titles like They Can Do it!, the Female Athlete, Issues with Coaching Girls, Designing Women, and Pregnancy and Other Practical Considerations. Clearly there is from the popular literature supporting the perception that there is nothing special that you need to know to coach boys, but there is important information you must have if you are going to coach girls. Although the focus of this talk is not on the social issues reflected in this disparity, interested readers should consult a recent content analysis of popular coaching books for an informed discussion of these issues (LaVoi, Becker, & Maxwell, 2007). The focus of this talk is on the empirical supporting the perception that there are differences in coaching boys as opposed to coaching girls. With regard to physical differences between men and women, there is substantial evidence. However, with regard to gender differences in psychological factors related to sport performance, there is very limited empirical and this has primarily been translated from research conducted in other venues such as educational settings, worksites, or personal relationships. In fact, the majority of the evidence for gender differences in psychological factors that are critical for coaches to be aware of appears to come from expert opinion or to be based upon experience and gender stereotypes. That being said, there is to suggest that there are small differences in communication between men and women (Allen & Valde, 2006). For example, men have been shown to be more talkative than women and to use more assertive speech whereas women use more afflliative speech (Leaper & Ayres, 2007). This is consistent with perceptions that women are rapport specialists who use communication to develop relationships while men use communication to problem solve and to aggressively focus on task accomplishment. Meta-analytic also indicates that all-female groups prefer a leader who uses a democratic style while all-male groups are more equivocal in terms of their preference for an autocratic or a democratic leader (Foels et al, 2000). There is some empirical of gender differences related to assertiveness and motivations for participation in intercollegiate sport. Men tend to report higher assertion scores than women (Keeler, 2007), and women report that they are less accepting of aggression in sport than are men (Tucker & Parks, 2001). Female athletes report a higher value for the social aspects of sport while male athletes more highly value the competitive nature of sport (Flood & Hellstedt, 1991). With regard to physical issues relevant to sport, there is empirical regarding pain perception and tolerance, injuries, and physical attributes. Although pain thresholds and pain tolerance are higher for the general population of men as compared to women (Riley et al., 1998), some suggests that there are no gender differences in pain intensity or affect amongst athletes (Hall & Davies, 1991). In terms of injuries, there are no differences in injury rates between boys and girls participating in youth (7-13 yrs) soccer (Radelet et al., 2002). In contrast, female high school athletes have greater overall injury rates than males in the sports of soccer and softball/baseball (Powell & Barber-Foss, 1999a) and have a greater rate of mild traumatic brain injuries (concussions) in the sports of soccer, basketball, and softball/ baseball (Powell & Barber-Foss, 1999b). …

Induction of All-male Groups in Red Sea Bream, Pagrus major, by Oral Administration of 17α-methyltestosterone

Induction of All-male Groups in Red Sea Bream, Pagrus major, by Oral Administration of 17α-methyltestosterone

Gender effects on tail damage development in single- or mixed-sex groups of weaned piglets

While extensive research on tail biting among pigs has focused on external factors (e.g., enrichment material), limited research has been conducted on internal factors (e.g., gender, breed or age), which may affect the predisposition of piglets to start tail biting. Furthermore, to test internal or external factors, most previous research used end point observations (e.g., tail damage at abattoirs). However, the potential factors causing tail biting, and the expression of tail biting itself can change over time as pigs grow older. Tail damage development over time might provide more accurate information on external and internal factors affecting tail biting than end point observation. Using tail damage development, we studied the effect of gender in single-sex and mixed-sex groups on tail biting. Tail damage development was recorded two ways: a) number of days before 40% of the piglets was observed with tail damage (40% incident point) and b) number of days a piglet was observed with tail damage (tail damage duration). A 2 × 2 factorial design was used and this resulted in four treatment categories: (1) all-male groups, (2) all-female groups, (3) males in mixed-sex groups and (4) females in mixed-sex groups. During the observation period tail damage (no damage, bite marks or tail wound) of 700 weaned piglets was scored three times per week for 32 days. Following the onset of tail biting, all-female groups had a lower 40% tail damage incident point (10.9 days), compared to the other three treatment categories (average of 16 days; P < 0.05). In all-female groups, piglets also had a higher tail damage duration (20.2 days), compared to the other three treatment categories (average of 16 days; P < 0.05). Several interactions between gender and mixing were found ( P < 0.05); males in mixed-sex groups had a lower 40% tail damage incident point and a higher tail damage duration than females in mixed-sex groups. These results indicate that female piglets are more likely to tail bite compared to male piglets. Furthermore, at the end of the observation period, tail damage had developed to high levels in all groups and, at that point, differences between all-female groups and the other groups were absent. Tail damage development is therefore a better way to analyse the effects of external and internal factors that result in tail biting, compared to methods based on end point analyses.

Social segregation in male, but not female yearling rhesus macaques (Macaca mulatta).

Males and females of many species sex-segregate, ranging from complete separation of habitats to social segregation within the same space, sometimes varying across seasons and lifespan development. Mechanisms for such segregation are not well understood, though some have suggested that sex differences in preferred juvenile behaviors lead to greater behavioral compatibility within than between sexes. This within-sex behavioral compatibility may be the source of sex-segregation. As juvenile behavioral sex differences are well-documented in rhesus monkeys, we examined sex-segregation patterns of yearling rhesus monkeys engaged in three different types of behavior: rough play, parallel play, and grooming. We observed male and female rhesus yearlings from five stable long-term age-graded social groups of 67-183 animals. Behavioral observations were designed to collect equal numbers of rough play, grooming, and parallel play bouts. In addition, sex composition and proximity to adults was recorded for each bout. Across all behaviors, more all-male groups and fewer mixed sex-groups were observed than expected by chance. All-female groups occurred at the level expected by chance. Thus, males sex-segregated regardless of type of behavior, while females did not sex-segregate. Female groups were observed in proximity to adults more often than expected by chance. These results suggest that behavioral compatibility may produce sex-segregation in male yearling rhesus monkeys, possibly preparing males and females for different social roles and segregation as adults.

Factors affecting wounding aggression in a colony of captive chimpanzees (Pan troglodytes)

Previous research has suggested that chimpanzees (Pan troglodytes) display higher levels of aggression in captivity than in the wild. One of the challenges of captive management, therefore, is to balance the chimpanzees' need for social interaction with managements' desire to minimize wounding and aggression. Various captive studies have examined the effects of individual and social variables on the frequency of wounding aggression, but none have examined these variables simultaneously. We collected retrospective wounding data for severe wounds from 83 captive chimpanzees (36 males, 47 females) from January 1993 to December 2003. The context of the wounding event, including individual age and sex, group age and sex composition, group duration, and portion of the week (weekday vs. weekend) were collected. Logistic regression analysis was performed to determine which variables had a significant effect on the probability of a severe wounding event. The sex and age composition of the group, group duration, and portion of the week had a statistically significant association with wounding. All-male groups (Odds Ratio (OR)=6.738) had the highest risk of wounding aggression, with uni-male groups (OR=3.311) having the next largest. Compared to individuals in all sub-adult groups, individuals in either all-adult (OR=4.516) or mixed-age (OR=3.587) groups had a higher risk of wounding. There was an inverse association between group duration and wounding (OR=0.821). Finally, there was an increased risk of wounding during the work week (OR=1.653). These results suggest that captive management should pay close attention to group composition, as well as levels of human activity, when devising strategies to reduce captive chimpanzee aggression.

Case study of a one‐sided attack by multiple troop members on a nontroop adolescent male and the death of Japanese macaques (Macaca fuscata)

An adolescent wild male Japanese macaque (Macaca fuscata), following Kinkazan A troop, was attacked one-sidedly by multiple members of the troop. The victim was identified as PI, and was estimated to be seven+/-one year old. The aggressive interaction was recorded by video camera until the end. Although at least 16 troop members approached PI more than once, only three males (one adult, two adolescents) of A troop attacked him. PI kept crouching throughout the attack, then escaped to the shore and dived into the sea. The interaction continued for more than one hour. PI was found dead a few hours after the end of interaction. The damage caused by the assailants was not the direct cause of PI's death; it was due to hypothermia caused by drifting in the sea. PI's life history was reconstructed from past records. PI was a normal adolescent male who migrated from an all-male group around B1 troop and started ranging around A troop. The aggressive interaction is believed to be a typical example of conflict between troop males and a nontroop male. The interaction period was very long compared with previous reports on such conflicts among Japanese macaques. PI kept crouching in open areas, exposing himself as a potential competitor for the resources of the troop, and did not show any submissive or reconciliatory behavior toward the troop males. This may be why the troop males did not stop the attack.

Resource distribution and group size in the common langur Semnopithecus entellus in southern India

We investigated the influence of resource abundance and distribution on the group size and composition of the common langur Semnopithecus entellus in the contiguous forests of Bandipur National Park, Mudumalai Wildlife Sanctuary and Nagarahole National Park in southern India. We also explored any additional effect of predator pressure and the risk of take-over on the same attributes. Data on group composition and vegetation were collected from January to May 2006. The size and composition of 94 bisexual groups were obtained. The group size varied from 7 to 40 and the groups included unimale and multimale groups. Thirty-five all-male groups were encountered. Vegetation was sampled from 17 grids of dimension 1 km x 1 km, each containing twelve 25 m x 25 m plots. The list of food species was compiled from previous studies and observations made during the study period. The mean basal area of all the food trees within each plot and its coefficient of variation at the level of the grid were used to represent resource abundance and distribution, respectively. The number of adult females and males within groups were analyzed separately to test for differential effects on age-sex categories. Group size increased as resources became spatially more heterogeneous. The abundance of resources had a negative effect on group size. This study did not find evidence supporting the direct effect of predator presence or of the risk of take-over. Contrary to what were expected, adult males reacted more strongly and predictably to resources than did adult females. The group attributes and their relationship with food resource abundance and distribution differed between two sites in the study area possibly owing to langur subspecies differences.

Aspects of Male Competition in Colobus vellerosus: Preliminary Data on Male and Female Loud Calling, and Infant Deaths After a Takeover

Male Colobus vellerosus are the main participants in intergroup encounters, and lead incursions in neighboring groups during which they attack infants. Extragroup copulations, all-male groups, and male takeover occur in the species. Here, we provide additional information on behaviors associated with male reproductive competition in Colobus vellerosus. We examined 1 resident male loud calling and participation in intergroup encounters in relation to a takeover. We also report a second case of takeover that led to the death of the former resident male and the death of 2 male infants, presumably as a result of aggression from the all-male group. The new resident male wounded the third infant of the group, which apparently died after its mother abandoned it. During the period characterized by the attacks on the infant and after its disappearance, females initiated and participated in loud call bouts with the new resident male. We examine the possible functions of female loud calling, and suggest that in this context, it might force the resident male to call along to indicate his presence.

Athletic Participation, Fraternity Membership, and Sexual Aggression Among College Men: A Meta-analytic Review

A meta-analysis of the data relating either college athletic participation or fraternity membership to attitudes and behaviors associated with sexual aggression was conducted with 29 studies which yielded 57 effect sizes. Membership in each male group was associated to a moderate extent with rape-supportive attitudes, and to a smaller extent with self-report of sexually aggressive behavior. There was much variability in the data that could be partially predicted by variables such as the size of the college, the validity of the study, and the age of the research participants. The involvement of these all-male groups in the perpetuation of hypermasculine attitudes (Mosher and Sirkin 1984) in a patriarchal culture was discussed.

Social compatibility in a newly formed all‐male group of white crowned mangabeys (Cercocebus atys lunulatus)

Surplus males in primate captive populations are a common problem for zoos. Some captive breeding programs promote all-male groups as an adequate option to house surplus males, but there have been few attempts to assess the feasibility of this management technique across primate species. The present study provides preliminary data regarding social compatibility within a newly formed all-male group of four white crowned mangabeys (Cercocebus atys lunulatus). The study was conducted at the Valencia Zoo (Spain), where data on social behavior were collected over 6 months using continuous focal animal sampling for a total of 87 hr of observation. Results show that low intensity aggressive behaviors (facial threats) were expressed at high rates, whereas physical aggression (fights) rarely occurred. Aggression was more frequent among individuals belonging to the same age-gender class. Regarding affiliative behaviors, every individual actively sought proximity to all other group members through positive approaches, and although not all males carried out social grooming, every male was groomed by at least one group member. Our results suggest that the group was compatible socially because social relationships among the individuals were not neutral, and physical aggression occurred at low rates. The present study provides preliminary data supporting the feasibility of all-male groups as a management option for surplus males in captive populations of white crowned mangabeys. Nevertheless, further studies are needed to be able to generalize both within and across species. Zoo Biol 0:1-7, 2007. (c) 2006 Wiley-Liss, Inc.

"I Read the Nikkei, Too": Crafting Positions of Authority and Masculinity in a Japanese Conversation

This article investigates how Japanese men use terms of address and sentence-final particles to create ongoing positions of superiority, seniority, and masculinity in their conversations. Data are drawn from conversations by all-male groups who are speakers of the Hanshinkan dialect of western Japan. An examination of real linguistic practices shows deft use of multiple linguistic features, including first-person pronouns, address terms, and sentence-final particles, to carve out particular identities vis-a-vis specific interlocutors. These forms and their subsequent stances are interpreted by other speakers in ways that indicate their access to larger discourses of ideological gender and hierarchy relations.

Leadership Structures in Same-Sex Task Groups

This article investigates contradictory findings reported in the literature concerning differences in leadership differentiation between same-sex groups. Drawing on arguments developed by Walker et al. (1996) addressing measurement validity in this literature, and on an extension in the status literature developed by Ridgeway (1988) and Fennell et al. (1978), this article develops and tests three predictions. Specifically, the authors predict greater differences in leadership differentiation between all-male and all-female groups when assessing leadership based on procedural behaviors than when assessing leadership based on influence. Also, leadership differentiation will be greater in all-male groups within a male-dominated organization, and in all-female groups within a female-dominated organization, than in all-female groups within a male-dominated organization when assessing leadership based on procedural compared with influence behaviors. Contrary to predictions, results show that all-male and all-female groups are equally likely to develop differentiated leadership structures when using procedural- and influenced-based measures. Implications of these results are discussed.

Female transfer between one-male groups of proboscis monkey (Nasalis larvatus)

Successful or unsuccessful female transfers were observed seven times during a 32-month field study of proboscis monkeys (Nasalis larvatus) inhabiting a riverine forest along a tributary of the Kinabatangan River, Sabah, Malaysia. In all cases, the females voluntarily left their own groups and immediately joined with another one. When adult females tried to shift to other groups, adult males called them back to their own groups, but appeared to be indifferent to subadult females. When the adult females returned, the males never attacked the females physically, but instead often emitted herding sounds to them. One subadult female was repelled by a resident adult female. When one adult female transferred into a new one-male group, she left her behind son in an all-male group. The number of females often fluctuated in most study groups, with this fluctuation being more prominent among subadult females than adult females. It is likely that female transfer in proboscis monkeys is not a rare occurrence and that it is especially common among sub-adult females.