All-male Groups Research Articles

Sex differences in the termination of social play in cats

Abstract Sixteen measures of social play between kittens were found to decrease significantly between 12 and 16 weeks of age. Behaviour was little influenced by the presence of the mother during this time. Although males' rates of behaviour did not differ from females' rates when the sexes were compared regardless of group composition, males from all-male groups played at higher rates than females from all-female groups. Females' rates of behaviour declined as the number of male companions decreased. Males' behaviour was little influenced by the number of females in the group. Females with male companions behaved more like males than did females with no male companions, but this was not because they directed behaviour to brothers at higher rates than to sisters.

The double standard of aging and the social situation: Judgments of attractiveness of the middle-aged woman

Two hundred male and 200 female undergraduates judged pictures of middle-aged women and middle-aged men for their “immediate emotional appeal.” Pictures had been selected to be of middle attractiveness and to represent individuals who appeared to be between 35 and 55 years old. Subjects made judgments under one of the following social conditions: in private, or in small groups which were all male, all female, or half male and half female. Social condition and subjects' sex affected judgments significantly, and there were some significant complex interactions between these two variables and the sex of the stimulus picture. Male and female subjects privately judged middle-aged women to be more attractive than middle-aged men, but the effect was reversed when judgments were made publicly in groups. As predicted, members of all-male groups judged middle-aged women to be considerably less attractive than middle-aged men. Members of all-female groups, and both the men and the women in mixed-sex groups, judged middle-aged women to be only slightly less attractive than middle-aged men.

EPA small pen tests I. Effects of pen and group sizes, sex combinations, and feeding levels on bobwhite activity.

Six-bird groups of bobwhites in large pens exhibited significantly more movement than did corresponding pairs of bobwhites in small pens, indicating a need to standarize pen and bird-group sizes in EPA small pen tests if results are to be comparable. Although in this study we did not detect any statistically significant differences in activity levels of bobwhites attributable to pen or bird-group size, the fact that the activity of pairs of bobwhites in small pens were consistently higher than those of 6-bird groups in larger pens reinforces the need to standardize pen and bird-group sizes in EPA small-pen tests. High er levels of aggression noted in the 6-bird groups compared with the 2-bird groups further substantiate this need. Additionally, the all-male 6-bird groups traveled significantly less distance than did male-female 6-bird groups, suggesting the need to also standardize sex combinations of birds used in EPA small pen tests. Dietary levels did not appear to affect either activity levels or movements of birds. Therefore this study produced no data to support the need to standardize dietary levels provided birds used in EPA small pen tests.

An Exploratory Analysis of Effect of Sex on Shift in Choices

This study investigated the effect of group composition by sex on choice shifts in group decision-making. The Choice Dilemmas Questionnaire was administered to 93 undergraduate students divided into same-sex or mixed-sex groups. The results suggest that groups' sex composition can affect group decisions. All-male groups tended to make slightly risky group decisions while all-female groups tended to be slightly cautious in their group decisions. However, a counterbalancing appears to occur in mixed-sex groups where no significant choice shifts appear in either direction.

Sex, Instructional Set, and Group Make-up: Organismic and Situational Factors Influencing Risk-Taking

The present piece of research was designed to investigate the effects of sex, type of instruction, and group composition on risk-taking behavior. Risk-oriented instructions produced significantly greater risk than neutral instructions for both individuals and groups. There were no significant shifts in risk when analyzing the difference between an individual's prescore and his score during group interaction. Males consistently demonstrated greater risk-taking behavior than females. Furthermore, all-male groups displayed more risk than either all-female, mixed-sex, or control groups. Plausible explanations were offered: sex-role stereotyping and consistency or congruity theory. Implications for research were discussed.

Effects of housing and rearing on age at puberty and libido in boars

ABSTRACTThe effects of type of housing (outdoors on earth v. confinement on concrete) and system of rearing (single v. group) on age at puberty and expression of libido in boars were examined. Boars kept on earth lots and reared in groups reached puberty earlier and demonstrated greater sexual aggressiveness compared with contemporary boars maintained under other treatment combinations. Additionally, the effect of rearing boars either in all-male groups or withprepubertal gilts was examined. Age at puberty was not affected by the presence of females, but boars reared without females attained a higher libido score.

Group treatment of single males with erectile dysfunction.

Nine men with chronic erectile dysfunction (three primary, six secondary) who had no regular sexual partner were treated in two 12-session all-male psychoeducational therapy groups. Treatment intervention addressed specific factors which inhibited adequate sexual function with a focus on coping skills to overcome those factors. Pre, post, and follow-up behavioral self-report data and responses on a goal attainment scale questionnaire indicated that the treatment groups were successful for five men with secondary and one man with primary erectile dysfunction. Subjective report and pre- and posttreatment fantasy productions to TAT cards for the first group indicated that all men significantly improved their attitudes about sexuality and their sexual self-concept. The results suggest that this is a viable, cost-effective treatment for secondary erectile dysfunction, but not for primary erectile dysfunction unless supplementary individual therapy is provided.

Effects of Group Characteristics on Social Space

A representational task employing top-view profiles was used to measure the social space of subjects toward groups in which structural characteristics were systematically varied. Three separate experiments were conducted. Females displayed larger social space than males toward groups of three and toward all-male groups. Semicircular and rank groups produced similar social space, and it was larger than that for file groups. Increases in group size affected social space for the semicircular and rank formations but not for the file formation. Group space increased with the number of males in the group and their proximity to the approaches Larger social space for groups of low than of high density indicated that both number of group members and area they occupied influenced social space.

Influences of sexual and social stimuli upon circulating levels of testosterone in male pigtail macaques

Circulating testosterone concentrations of adult male pigtail macaques (Macaca nemestrina) were assessed in three social conditions: (1) subjects housed in a stable heterosexual group (continuous contact with females); (2) subjects housed in an all-male group (no contact with females); and (3) subjects housed in a newly established heterosexual group (female presence as novel stimulus). Pigtail males living continuously with females throughout the year did not exhibit seasonal cyclicity in testosterone values and maintained mean levels equivalent to those observed in the rhesus monkey during the breeding season. Members of all-male groups had mean testosterone concentrations equivalent to males living with females, but these values rose significantly following the addition of females to the group.

Behavioral Observations on Oryx Antelope (Oryx beisa) Invading Serengeti National Park, Tanzania

In 1959 a boundary change in the Serengeti National Park excluded the area inhabited by oryx antelope. During the following years, only a few solitary animals came temporarily into the park. Beginning in 1972, oryx invaded the southeastern part of the park more frequently and in larger numbers. Recent observations (1974–1975) show that oryx are still only visitors to the Serengeti National Park, but there are indications that they may become resident in the future. Compared with a resident oryx population in the Tarangire National Park, the wandering herds in Serengeti were characterized by (a) a more frequent occurrence of mixed herds of some size, (b) the absence of subadults and juveniles, and (c) the absence of female groups. Small all-male groups, “harem” groups, and solitary adult bulls were recorded in both areas. Oryx exhibit a polyphasic rhythm of daily activity. Except when large concentrations of wildebeest arrive in an area, oryx do not avoid the company of other game species, although they hardly interact with them. A hierarchical organization was recognizable in all the groups observed. Generally bulls ranked over cows, but sometimes subadult or young-adult bulls were dominated by high-ranking cows. Fights among bulls were quite frequent. In addition to spontaneous sparring matches, these agonistic interactions were linked with coordination of group activities, with frontal approaches of group members at close range, particularly in grazing, and with strange bulls joining a herd. The severest fight observed took place between the alpha-bull of a mixed herd and a solitary bull. Peers challenge each other by equivalent, reciprocal displays until fighting develops. In an encounter of unequal opponents, only the dominant animal shows dominance and/or offensive threat displays. The subordinate responds by defensive threats and/or submissive displays. Such a “dominance encounter” ends with the withdrawal of the subordinate without a fight. An alpha-bull of a mixed herd does not fight the subordinate bulls, but frequently has “dominance encounters” with them. In this way, the alpha-bull reinforces his dominance over the others, affects changes in the activity of the group, influences speed, length, and direction of movements, and prevents members of the group, including subordinate bulls, from leaving.

Influence of social conditions during rearing on the sexual behaviour of the domestic boar

SUMMARYThree groups of six young male pigs (boars) were reared from 20 days to 7 mo of age under one of the following social conditions: a mixed sex group; an all-male group; or social restriction, without physical and visual contact with other pigs. The sexual behaviour of the boars was studied from 7 to 13 mo of age. The total number of copulations and the sum of all the courting behaviour activities were significantly greater (P<0·01) for the boars reared in the all-male and the mixed sex groups than for those reared in social restriction. Growth rate to 30 weeks of age, testicle size and semen quality were not affected by rearing treatment.

Plasma concentrations of testosterone in the developing ram in different social environments

Plasma testosterone profiles were determined by taking frequent blood samples at intervals from birth to 21 months of age from rams reared in isolation, in an all-male group and in a mixed-sex group. The testosterone pattern was not modified by these different social environments. The ability of the ram to copulate when first exposed to an oestrous ewe, apparently a maturational process, was also independent of social rearing. At birth plasma testosterone levels were detectable but low, they were higher at 10 and 16 weeks of age and showed a marked rise by 26 weeks, coincident with the time of puberty. Depressive effects of season on testosterone profiles occurred during the 2nd year of life but not the 1st year.

L’écologie de Mungotictis decemlineata dans les forêts décidues de l’ouest de Madagascar

A wild population of the endemic Madagascar mungoose Mungotictis decemlineata was studied in 1974 and 1975 near Analabe, W. Madagascar. Some individuals were «tail-marked » and followed by radio-tracking. Five months were spent in the field at different seasons of the year. Mungotictis decemlineata lives in a dry forest whose primary productivity is highly seasonal, occuring mostly during the rainy period of the austral summer. This Madagascar mungoose is diurnal in habits. The night is spent in tree holes during the wet summer and in ground burrows during the dry winter. Several individuals of the same social group may congregate to spend the night in the same shelter which often varies from day to day. In the absence of old abandonned ant-hills, Mungotictis can dig by itself his own ground burrows. The diurnal activity period is longer during the rainy season than during the winter. Mungotictis is both terrestrial and arboreal. It can climb trees, bear like, up to a diameter of about a foot ; however it usually prefers smaller trunks and vines. The diet is mostly insectivorous. The stapple food, especially in winter time, consists of insect larvae, which they extract from the ground (mostly larvae of Tenebrionid beetles and Heteronychus) or from dead wood (larvae of Cetonid and Elaterid beetles). This insect diet is supplemented, especially in summer, by millipedes, snails, amphibians, lizards and mouse lemurs. Grouphunting of Microcebus murinus and chamaeleons has been observed. Up to 20 g of insect larvae (fresh weight) can be consumed per individual per day. The 22 individuals living in an area of 300 hectares were permanently divided into two stable social units, here called «super-groups», within which the inter-individual social relationships were very variable depending on the season. Broadly speaking adult males and females tended to come together during the summer and to split during the winter into smaller groups. These winter social units were very variable : temporary pairs, maternal family parties, all-male groups or even solitary males. Such a dry-season scattering of the ««super-group» members may be considered as an adaptation to the pattern of distribution of the available food sources. Two-year old juveniles leave their mothers at the time of the breeding season (February and March). Agonistic behaviours were observed both around the winter feeding areas in which insect larvae were plentiful, and, at all times of the year, in the border zone between the «territories » of two adjacent «super.groups».

Strange females increase plasma testosterone levels in male mice.

Male house mice paired with a normal female for 1 week do not have higher plasma testosterone levels than do males that remain in all-male groups, but paired males have markedly elevated testosterone levels 30 to 60 minutes after the resident female is replaced by another female. Elevation of testosterone levels in these males is similar to that in isolated males paired with a female, does not depend on copulation with the strange female, occurs under housing conditions that permit continuous exposure to the odors of other females and males, and does not occur when the resident female is replaced by another male for 30 to 60 minutes. The elevation thus appears to be a specific endocrine response to an encounter with a strange female. These results, along with previous findings suggesting that strange males affect endocrine function in females, indicate that bisexual encounters are likely to produce endocrine changes in members of both sexes.

Betting Behavior in Sexually Homogeneous and Heterogeneous Groups

Groups of undergraduates, 4 males, 4 females, 3 males-1 female, or 3 females-1 male made bets in an individual condition (Phase I). One-half the groups were then transferred to a group condition in which Ss knew the bets of other group members and one-half continued to make bets in the individual condition (Phase II). In Phase I males were more risky than females. In Phase II Ss in the group condition were more risky than those in the individual condition and males were more risky than females in both the individual and group conditions. In the group condition males in all-male groups and with one female in the group shifted toward risk, but males with three females in the group shifted toward caution. In the group condition females in all-female groups were cautious, became slightly more risky with one male in the group, and showed a marked shift toward risk with three males in the group These results are similar to the Asch (1952) conformity studies and suggest that shifts toward risk or caution are due to conformity to group pressure.

Plasma testosterone levels in the male rhesus: influences of sexual and social stimuli.

Four adult male rhesus monkeys were provided access individually to a group of receptive females. Each male assumed dominance and engaged in frequent copulations. Plasma testosterone levels increased two- to threefold during this period. Next, each male was subjected to sudden and decisive defeat by a large all-male group, and plasma testosterone fell following this experience. Two males were later reintroduced to the females, and plasma testosterone rose rapidly to the previous elevated levels.

Crowding and human aggressiveness

Two experiments investigated the effect of crowding on human aggressiveness by placing groups of Ss in small or large rooms for several hours. In both experiments there was no main effect of crowding but there was an interaction between sex of subject in one-sex groups and the size of the room. In Expt. I, all-male groups were more competitive in small rooms while all-female groups were less competitive in small rooms. In Expt. II, all-male groups gave more severe sentences in a small room than in a large room while all-female groups were more lenient in the small than the large room. Mixed-sex groups showed no effect of room size for either the whole group or each sex considered separately. Affective reactions by the same sex groups were consistent with these measures, males being generally more positive to each other in the experiment in the large room while females were more positive in the small room. It is concluded that crowding does not have a generally negative effect on humans and that what effects it does have are mediated by other factors in the situation. An explanation of the sex-difference is offered.

Roles and Activities of Male Geladas (Theropithecus Gelada)

AbstractTheropithecus gclada males may live in all-male groups, one-male groups, or in isolation. They play different roles in these different groups. Two recording techniques were developed to quantify the activities and interactions of the male geladas. There was found to be a significant relationship between a male's activities and interactions and the role he plays. There were found to be patterns of activities and interactions which correspond to male roles. These are described.

Colobus guereza : Territoriality and Group Composition

Troops of the black and white colobus Colobus guereza in the Bueclongio Forest, Uganda, average eight animals with a typical composition of one adult male, four adult females, two subadults, one juvenile, and one infant. Solitary males and small all-male groups also occur. Troops of mixed sexes have well-defined territories which coincide roughly with the home range. Territories of five groups averaged 0.062 square mile (0.137 kmn(2)) in area agreeing closely with territory-sizes of Asian Colobine monkeys. Adult males have a roar that is concerned with maintaining territorial spacing, but not with actual territorial defense. The territories of these arboreal, forest animals are much smaller than the home ranges of more terrestrial and nonterritorial open-country primaes.

Effects of prepubertal habitation conditions on the reproductive physiology of the male house mouse.

Summary. Male albino and wild house mice were reared from weaning (at 21 days) either to 37 or 56 days of age in: (1) isolation, (2) all-male groups of four, or (3) all-male groups of four in cohabitation with an adult female. At 37 days the cohabiting albino males exhibited larger testes and epididymides than animals in the other two situations. Similarly, they had larger seminiferous tubules and were significantly more mature (by an arbitrary rating system) than the isolated males or the males in all-male groups. Wild males reared in isolation or in cohabitation were reproductively superior in essentially the same fashion to males in all-male groups. Cohabiting wild males, however, were significantly more mature than wild males in either of the other two conditions. When reared to 56 days, albino males in cohabitation exhibited a high degree of social conflict and were reproductively inferior to both the isolates and the males in all-male groups. In contrast, cohabiting wild males at 56 days of age showed reproductive growth equal to that of males in all-male groups. However, both albino and wild adult males in cohabitation exhibited none of the reproductive advantages seen in 37-day-old cohabiting males. In a final set of studies it was shown that albino males reared to 37 days of age with intact females had larger testes, epididymides and seminiferous tubules and significantly higher concentrations of epididymal spermatozoa than male litter-mates reared with ovariectomized females. Wild males reared with intact females, while failing to show larger testicular and epididymal weights, did possess larger seminiferous tubules than wild males with ovariectomized females. Those studies show that the presence of an intact female bestows reproductive advantages upon groups of young male mice. These advantages do not persist to adulthood.