Measuring male-female relationships during the mating season in wild Japanese macaques (Macaca fuscata yakui)

Heterosexual relationships during one mating season were examined in a wild troop of Japanese macaques (Macaca fuscata yakui) on Yakushima Island, Japan. Validation tests of putative mate choice behaviors demonstrated that female initiation and maintenance of proximity, female lookback at the male, and sexual presents to the male, were associated with increased mating. Male grooming the female was also associated with increased mating. Ten dyadic social behaviors were subject to principal components analysis to empirically define behavioral dimensions of male-female relationships. The analysis yielded four relationship dimensions: ‘Mutual Choice and Male Coercion,’ ‘Female Choice’ (two types), and ‘Mutual Choice’ Dyads tended to be characterized by more than one dimension. The results suggested that females sought matings with multiple males of various dominance ranks. Female relationships with high ranking males contained elements of male coercion and mate guarding, however, because these males attempted to inhibit females from mating with lower ranking males. The correlation between each relationship dimension and mating success depended, in part, on the dominance rank of males. Relationships involving high ranking males, which were most likely to contain elements of male coercion and mate guarding, were associated with mating success. Relationships involving low ranking males, which usually lacked such coercive elements. were less strongly correlated with mating success. These results, obtained from a wild troop, are compared to those previously obtained in captive and provisioned groups of Japanese macaques.     

Territorial behaviour in corn mice, <Emphasis Type="Italic">Calomys musculinus</Emphasis> (Muridae: Sigmodontinae), with regard to mating system

We studied territorial behaviour of Calomys musculinus, a promiscuous-polygynous species, in order to test the predictions that during the breeding period, home-range-owner females are more aggressive than home-range intruders and that males do not display territorial behaviour. At the core of the breeding season, we conducted 136 intrasexual and 66 intersexual encounters. The study was carried out in four 0.25-ha enclosures, each containing one independent population. We studied territorial behaviour utilising focal animal sampling to record behaviour. Encounters were conducted in a circular opaque arena (COA) near the home-range’s activity mathematical centre (AMC). Amicable behaviour was not observed in any of the 78 trials among females. The rates of aggressive and submissive behaviour per female–female encounters varied in relation to whether they were home-range owners or intruders, the former being aggressive, the latter submissive. So we could link these drives to the territorial behaviour of C. musculinus. This result fits well with the already known territoriality of C. musculinus during the breeding season. In contrast, the 58 intrasexual male encounters did not show direct aggressive interactions between them. The rates of the different behaviours between males did not vary in relation to whether they were home-range owners or intruders. In our study, which took place during the breeding period, C. musculinus males were nonterritorial, and they never exhibited aggressiveness towards females.     

Mating patterns,mate choice,and birth season heterosexual relationships in free-ranging rhesus macaques

Birth season adult heterosexual nonkin relationships of 50 free-ranging female rhesus macaques (Macaca mulatta) in two social groups at Cayo Santiago, Puerto Rico were examined using focal follow (289 hr) and ad lib data. Eighty-eight percent of subjects had at least one relationship characterized by particularly high frequencies of spatial proximity, grooming, or both. These were designated “friendships.” Males intervened in aggressive interactions more frequently on behalf of Friends than non-Friends. Female aggressive support of males was extremely rare. Higher-ranking males experienced more friendships than lower-ranking males. High-ranking females had higher-ranking Friends than low-ranking females. Older females had higher-ranking Friends than younger females. Females groomed high-ranking Friends more than they were groomed by them, whereas they groomed low-ranking Friends less than they were groomed by them. In one social group, high-ranking females were more likely than low-ranking females to groom their Friends more than they were groomed by them. Males were more responsible than females for spatial proximity maintenance in 9 of 14 Friend dyads for which sufficient data were available. Neither male nor female dominance rank affected responsibility for proximity maintenance in Friend dyads. Eight of 24 females had friendships with males with whom they had completed copulations during their conception peri-ovulatory period of the preceding mating season. Two of 19 females completed peri-ovulatory copulations with Friends during the following mating season. Friendship was not correlated with either of two demonstrated female mate choice indicators: (1) proximity maintenance during estrus; or (2) cooperation with male “hip-grasp” courtship attempts. Males directed “muzzle-up” courtship signals at lower rates toward Friends than toward non-Friends. These and other investigators' results indicate that (1) protection from aggression is the primary benefit to female rhesus macaques of birth season heterosexual relationships; (2) the most effective protectors are in greatest demand as Friends; and (3) friendship has no effect or an inhibitory effect on mate choice in this species. Benefits to males of friendships were not apparent from this study but may include coalitional support against lower-ranking males.     

Social interactions associated with reproduction in the bushveld gerbil <Emphasis Type="Italic">Gerbilliscus leucogaster</Emphasis>

The study of social behaviour can give us important insights into the social and mating system of a species or population. We investigated male–female interactions in captive bushveld gerbils, Gerbilliscus leucogaster, to gain insight into the social behaviour and mating structure. We conducted two experiments. In experiment 1, we studied the interactions between two strangers for a week in a three-tank setup, which tested behavioural variation spatially and temporally. Although tolerance between strange males and females increased with time, it remained generally low throughout the experiment. Females appeared to be cautious of males initially, but they later became aggressive towards them. Males showed an increase in submissive behaviour over time. The ‘home’ cage did not appear to be defended by either sex. In experiment 2, we investigated the social interactions of male–female pairs during pregnancy and lactation. Aggression persisted throughout the study and amicable behaviour was low; females were much more aggressive than males. We did not detect changes in social behaviour with the progression of pregnancy and lactation. We suggest that pair bonding is unlikely and that promiscuity is the most probable mating system. Female aggression may be related to mate choice prior to mating and mate exclusion thereafter, while it may be a response to infanticide risk during pregnancy and lactation.     

Social behaviour and infant carrying in a group of moustached tamarins,Saguinus mystax (primates: Platyrrhini: Callitrichidae), on Padre Isla,Peruvian Amazonia

The social behaviour of a group of eight moustached tamarins,Saguinus mystax, (five males, three females) was studied on Padre Isla in northeastern Peru. About 60% of all allogrooming was done by the two adult males in the group, and about 11% by a young adult female. All other group members groomed very little. The adult breeding female received more grooming than any other group member. After the death of the adult female (preyed upon by an anaconda) the amount of active allogrooming remained constant for all group members except for the young adult female, who increased her contribution to about 30%. Her preferred grooming partner was the subadult female, which generally screamed when being groomed by the young adult female and terminated grooming by going away. This kind of grooming relation is termed “forced grooming” and is interpreted as a possible social control mechanism. The young adult female groomed the adult males more often after the death of the adult female than before. This might have had the function of strengthening the social bond with the adult males and in obtaining the breeding position in the group. After the death of the adult female, the vulva of the young adult female grew to full adult size. Agonistic behaviour was less frequent than allogrooming. Most aggressive interactions (50%) originated from the subadult male of the group. The young adult female was the target of most of these aggressions. Extremely little aggression occurred between the three females. The young adult female was the only individual who tried to emigrate from the group during the study period. Her attempt to join a neighbour group failed due to rejection by all four members of this group. All group members participated in carrying an infant, but the adult males and the young adult female carried most frequently. Contribution to infant carrying varied with the infant's age.     

Sexual behaviour of immature male eastern mosquitofish: a way to measure intensity of intra-sexual selection?

Immature males of eastern mosquitofish Gambusia holbrooki start to be sexually active well before their copulatory organ (gonopodium) has completely developed and before they become able to transfer sperm. Sexual activity of males, consisting of copulatory attempts tending to bypass female acceptance, is intense (one attempt per minute) and is likely to be energetically very costly. The sexual behaviour of immature males relative to their maturation stage is described and tested against two possible adaptive explanations. Sexual activity was present in males from the beginning of the development of their gonopodium and increased during the following stages of maturation. Two to three weeks before gonopodium development was completed, sexual activity of immatures was as high as that of adults. Adult males showed aggressive behaviour against a male attempting a copulation, irrespective of the maturity of the latter. Since previous studies have shown that the reproductive success in this species is negatively correlated with male size when male–male competition is low (i.e. when the sex ratio is female biased), but decreases with male size when competition is high, the hypothesis was tested that sexual activity of immature males functions as a way to predict their future reproductive success if they mature at a given size. A second hypothesis tested was that precocious sexual experience improves the efficiency of copulatory attempts. Results were more in agreement with the first hypothesis, since size at maturity of males was influenced by the sex ratio experienced during maturation and precocious experience gave very little advantage.     

Aggressive behaviour in Montagu’s harrier Circus pygargus during the courtship period

Aggressive behaviour of Montagu’s harrier was observed during the pre-laying period in the 1992–1995 seasons on the calcareous marshes of Chelm in Eastern Poland. In total, 435 flights performed by 24 pairs of individually marked harriers were analysed. All flights were performed in relation to the territory of defence. Males performed 61% of aggressive interactions while females performed 39%. Intraspecific and interspecific aggression comprising direct attacks (58%), escorts (13%), pursuits (28%) and “mirror behaviour” (1%) were described for the first time. Interspecific aggressive behaviour occurred only near territory boundaries. The main intruders were marsh harriers Circus aeruginosus breeding on the same marshes. Occasionally, harriers attacked curlews Numenius arquata, short-eared owls Asio flammeus, magpies Pica pica, hooded crows Corvus corone cornix, common buzzards Buteo buteo or hobbies Falco subbuteo. Four cases of communal mobbing were observed. Three to five males from the neighbourhood attacked the intruders together. Intraspecific aggressive behaviour was observed in the pair territory, near the boundary or at a distance of up to 100 m from the defended area. Aggressive interactions performed by both sexes were more frequent towards birds of the same sex. Females defended their territories more aggressively against females. Similarly, males were more aggressive against males. All cases of aggressive behaviour were observed near harrier territories. Aggressive relations between birds outside breeding territories or when foraging around marshes were not observed.     

Ontogeny of Aggressive Behaviour in Schools of Yellowtail, Seriola Quinqueradiata

We studied ontogenetic changes in social interactions, especially in aggressive behaviour of the migratory marine yellowtail, Seriola quinqueradiata (Carangidae), and compared these to morphological and physiological changes. No agonistic interactions were observed during the larva period until 10 mm in total length (TL), at approximately 20 days after hatching. Typical shivering behaviour with J-posture was observed during metamorphosis, when fin rays and calcification of vertebra were completed and there was an increase of tissue thyroid hormone. The onset of aggressive behaviour was just after metamorphosis to the juvenile period, and coincided with a significant increase in tissue cortisol levels. The onset of schooling behaviour was at 12 mm TL, slightly after the onset of aggressive behaviour. From observations of individual aggressive behaviour within juvenile schools, we found three categories of social rank: dominants (10-20%), intermediates (10-20%), and subordinates (60-80%). There was an inverse relationship between social rank and cortisol concentration. Otoliths of dominant fish in 8 experimental groups were labeled and the fish were returned to their groups. Six labeled dominants appeared after 1 day and three after 1 week rearing, respectively, indicating that social rank was maintained for at least 1 week (binomial distribution, p < 0.05). Dominants were larger than subordinates after 1 day rearing, whereas dominants were smaller after 1 week rearing. From long-term rearing experiments using individual otolith marking, larvae that showed the J-posture more frequently tended to become dominants after metamorphosis, indicating a positive correlation between the J-posture and aggressive behaviour. Synthesizing all results from behavioural experiments, we generated a behavioural model for the triggering mechanism of aggressive behaviour and size selection of school members.     

Interactions among adult males and females before and after the death of the alpha male in a free-ranging troop of Japanese macaques

This report documents the social interactions among adult Japanese macaques in a free-ranging troop before and after the death of the alpha male, who died at 28 years of age after occupying his rank position for 17 years. The alpha male’s physical condition had deteriorated due to his extreme age for several months before his death. However, he maintained his alpha position. When he was attacked by the second-ranking adult male, he was rescued by the alpha female. Thereafter, whenever the second-ranking male approached him, the alpha male screamed for the alpha female’s support. The number of adult females to whom the alpha male maintained proximity during his last four months was similar to that during the same period of the previous year. Prior to his death, the alpha male was observed in close proximity to the alpha female much more frequently than was the second-ranking male. These results indicate that the alpha male maintained his position by depending on female support and particularly that of the alpha female.     

The effect of carbon dioxide enrichment on apparent stem respiration from <Emphasis Type="Italic">Pinus taeda</Emphasis> L. is confounded by high levels of soil carbon dioxide

Huey and Slatkin’s (Q Rev Biol 51:363–384, 1976) cost–benefit model of lizard thermoregulation predicts variation in thermoregulatory strategies (from active thermoregulation to thermoconformity) with respect to the costs and benefits of the thermoregulatory behaviour and the thermal quality of the environment. Although this framework has been widely employed in correlative field studies, experimental tests aiming to evaluate the model are scarce. We conducted laboratory experiments to see whether the common lizard Zootoca vivipara, an active and effective thermoregulator in the field, can alter its thermoregulatory behaviour in response to differences in perceived predation risk and food supply in a constant thermal environment. Predation risk and food supply were represented by chemical cues of a sympatric snake predator and the lizards’ food in the laboratory, respectively. We also compared males and postpartum females, which have different preferred or “target” body temperatures. Both sexes thermoregulated actively in all treatments. We detected sex-specific differences in the way lizards adjusted their accuracy of thermoregulation to the treatments: males were less accurate in the predation treatment, while no such effects were detected in females. Neither sex reacted to the food treatment. With regard to the two main types of thermoregulatory behaviour (activity and microhabitat selection), the treatments had no significant effects. However, postpartum females were more active than males in all treatments. Our results further stress that increasing physiological performance by active thermoregulation has high priority in lizard behaviour, but also shows that lizards can indeed shift their accuracy of thermoregulation in response to costs with possible immediate negative fitness effects (i.e. predation-caused mortality).     

Social behavior of infant and mother Japanese Macaques (Macaca fuscata): Effects of kinship,partner sex,and infant sex

The behavioral interactions of 22 infant and mother Japanese macaques with other group members were studied. Focal-animal observations were made from the time of each infant’s birth until 1 year of age. Infants and mothers both displayed exceedingly strong preferences for associating with matrilineal kin and, specifically, for female kin. The degree of genetic relatedness was positively correlated with levels of spatial proximity, contact, grooming, aggression, and play. Overall frequencies of interactions with nonkin were very low, and partner sex was not an important factor in interactions with nonkin. There were no significant differences between male and female infants in interactions with kin versus nonkin. There was only one significant difference between male and female infants in interactions with males versus females: female infants showed stronger preferences for initiating proximity with females over males than did male infants. Because mothers provide the focal point for infant interactions during the first year of life, we compared the behavior of infants and mothers. Mothers were the recipients of more social interactions than were infants, mothers engaged in more grooming than did infants, and infants engaged in more social play than did mothers. These findings are only partially consistent with kin-selection theory, and the inadequacies of studying matrilineal kin discrimination to test kin selection are reviewed. The near-absence of infant sex differences in associations with social partners suggests that although maternal kin other than the mother are important to infant socialization, they probably do not contribute to the development of behavioral sex differences until after the first year of life.     

Male collared lizards,Crotaphytus collaris (Sauria: Crotaphytidae), signal females by broadcasting visual displays

The signalling function of displays broadcast when animals are distant from conspecifics can be difficult to determine. I tested the extent to which visually transmitted broadcast displays given by free‐ranging territorial male collared lizards signalled same‐sex rivals or females. One test involved recording the frequency of broadcast displays, aggressive contests with rivals, and courtship encounters with females during ten reproductive seasons when local sex ratios varied markedly. The frequency of broadcast displays decreased as the ratio of male competitors to females increased. The frequency with which males initiated contests with rivals was not related to the ratio of competitors to females, whereas the frequency of courtship interactions decreased with sex ratio because there were fewer females to court. The behaviour of males that defended territories during two successive seasons showed a similar pattern. Broadcast display frequency was positively correlated with courtship frequency, but not with the frequency of contests with rivals. Lastly, individual males gave more broadcast displays during focal observations when they also engaged in courtship encounters with females than other observations when they engaged in aggressive conflicts with rival males. Although these results do not reject the possibility that broadcast displays may also signal male rivals, they support a major role of these displays in advertisement to females. © 2013 The Linnean Society of London     

Advanced sub social behaviour in the scorpionHeterometrus fulvipes Brunner (Arachnida)

Scorpions arc generally non-social, solitary animals that interact with conspecifics at birth, courtship or predation only. The present study reports the presence of advanced sub social behaviour inHeterometrus fulvipes Brunner and evaluates the importance of its burrowing as a cause for such social behaviour.Heterometrus fulvipes constructed deep angular burrows at the base of plants. Burrows provided (i) protection against predation, (ii) increased availability of food and (iii) ideal microclimate for year round activity of the scorpions. No cannibalism was observed in laboratory maintained colonies. The risk of predation and the difficult by immatures to dig tunnels during dry soil conditions may have forced the mother and offspring to live together in the burrow for longer durations. The cohabitation of relative offsprings transforms the burrow into a nest. The members of a colony exhibits division of labour for nest expansion and in foraging. The mother communicates with the immatures through “Buzz” sound and may provide premasticated food. There is food sharing also among colony members. All these behaviours indicate the presence of advanced sub social behaviour inHeterometrus fulvipes.     

Settlement Patterns of Mediterranean Fruit Flies in the Tree Canopy: An Experimental Analysis

Males of the Mediterranean fruit fly, Ceratitis capitata (medfly), defend individual leaves of host and non-host trees as mating territories and attract females via production of a sex pheromone (a behavior termed ‘calling’). Males tend to aggregate within the tree canopy, and the present study examined the influence of (1) location and (2) resources on female visitation to male aggregations. Males were placed in screen-covered containers, which were suspended on field-caged trees at two locations selected to differ in only one of the following parameters: height above ground (low versus high), leaf density (sparse versus dense), distance to main trunk (canopy edge versus center), proximity to a food source (bird feces absent or present), and proximity to a host fruit (oranges absent or present). Females were released, and we periodically recorded the number of calling males in each of the test aggregations as well as the number of females sighted within 15 cm of each male aggregation. Male calling did not differ between treatments in any of the experiments. However, females were more frequently sighted near males calling (1) in dense foliage, (2) near the central trunk, (3) near bird feces, and (4) near oranges. In an additional experiment, we compared male settlement (in the absence of females) on leaves in the same sites used previously to determine the degree of congruence between the sexes in microhabitat use. Aside from the lack of center-edge effect, males displayed the same settlement patterns as females. In a final experiment, we found no effect of male calling on the distribution of other males: released males were sighted with equal frequency near cups containing mature, calling males and cups containing immature, non-calling males. Medfly lek behavior is discussed in light of these findings.     

Effect of stress-inducing factors on monkey behavior. II. Hormonal indices and their relation to behavior in the modelling of emotional stress in hamadryas baboons

The behavioural and hormonal indexes of adult males Papio hamadryas have been examined under condition of immobilized stress. The intercommunication between the hormonal status of the individual and its position in the hierarchical structure of the group is marked. The leader of the group possesses the mostly constant hormonal content during the different periods of the stress. The equal speed of reconstruction of hormonal concentration and behavioural indexes has been found. The different types of correlation between the level of adrenaline, cortisol and testosterone secretion and the frequency of aggressive behaviour have been observed.     

Non-reproductive copulation behavior among Tibetan macaques (<Emphasis Type="Italic">Macaca thibetana</Emphasis>) at Huangshan,China

Non-reproductive copulation, which takes place outside of the mating season and does not result in conception and birth, was studied in a free-ranging group of Tibetan monkeys (Macaca thibetana) at Mt. Huangshan, China, in the birth seasons of 1992 and 1997. We employed all occurrence and focal animal samplings to record sexual and related behaviors and affiliation interactions, respectively. Compared with sexual behavior in mating season, non-reproductive copulation occurred at a lower frequency, with less frequent ejaculation, less harassment, shorter mount duration, and an absence of pause with vocalization. It often took place in a situation in which non-lactating females were involved in social conflict or approached males for mating. Neither pregnant nor lactating females were observed to mate in the birth seasons. Copulation during the birth season did not increase a sexually receptive female’s delivery the next year, nor was it associated with increased proximity, grooming, or agonistic aid for the mating pair. However, copulated pairs spent more time co-feeding, presumably reflecting an increased tolerance on the part of the male. Adolescent males, who rarely copulated in the mating season, engaged in mating activity in birth seasons as well. Therefore, though birth-season copulation had no reproductive functions, it may have fulfilled social functions for females, such as post-aggression appeasing by males or gaining access to resources. This also offered good opportunities for adolescent males and females to develop their sexual skills for later competition.     

Intermale relations and troop male membership changes in langurs (Presbytis entellus) in Nepal

Data on intermale social relations and troop membership changes in one Nepalese high-altitude population of free-ranging langurs (Presbytis entellus)are reported here. Data were collected from six troops by three observers and cover 32 months of observations. The predominantly multi-male troops indicate an alternating pattern of exclusions and introductions with gradual adult male replacement. Takeovers and infant killing were not observed. Analysis of adult social behavior records show qualitative and quantitative differences in intrasexual relations, with primarily agonistic social contacts occurring between males. Agonistic encounters between females and between males differ in frequency of occurrence, types of be-haviors used, cause, and consistency in direction of threats between individuals. Individual adult male frequency of interaction with females and immatures varied significantly, with the majority of these interactions occurring between the dominant troop male and other troop members. Data indicate that intermale dominance is a major factor in determining male access to fertile females: This appears to be achieved by either directly excluding males from the troop or effectively “controlling” their inter-actions with troop females. Data from these studies are compared with data from other Presbytis entellusinvestigations. Review of these data suggests that intraspecific variability in intermale social dynamics and type of troop male membership change are correlated with the percentage of nontroop males. It is suggested that environmental pressures resulting in social crowding can be critical in determing the occurrence of takeovers in some populations of Presbytis entellus.     

Affiliative relationships between adult males and immature group members in naturally occurring ringtailed lemurs (Lemur catta)

Affiliative relations between adult males and immature group members were studied in three naturally occurring groups of ringtailed lemurs (Lemur catta) over a 12-month period at Beza-Mahafaly Reserve, southwestern Madagascar. No statistically significant difference was found in rates of affiliative interactions between adult males and older immatures (juveniles and adolescents) over reproductive seasons. However, some of the adult males in two focal groups increased their rates of affiliative behaviors with older immatures during the lactation and subsequent 1993 postmigration periods. Female involvement with infants during lactation season, the increasing independence of juveniles and adolescents, and length of male tenure may be factors contributing to such a pattern. Neither adult males nor immatures were significantly responsible for the initiation and maintenance of proximity in male-immature dyadic interactions. Neither dominance rank nor age-class of the adult male affected their rates of affiliative behavior with immatures. The majority of focal males exhibited an interest in infants and occasionally participated in alloparental care. It is suggested that adult males can benefit from affiliative relations with immatures in terms of opportunities for greater spatial centrality in the group, which can lead to enhanced predator protection and greater opportunities to develop affiliative relationships with females. Immatures can benefit from affiliation with males in relation to enhanced predator detection and protection, alloparental care, and opportunities to develop social skills. Am J Phys Anthropol 103:163–171, 1997. © 1997 Wiley-Liss, Inc.     

Predatory behaviour of common kestrels (Falco tinnunculus) in the wild

The predatory behaviour of eight wild adult common kestrels (Falco tinnunculus) was recorded during predatory tests carried out in the wild under controlled conditions. Those birds were offered one laboratory mouse each, which was restrained on a base, thereby simulating natural predation. The predatory sequence was recorded directly, but also video-taped. The sequence was rather homogeneous among the kestrels, with most kestrels starting the attack glide from a perch, then capturing the prey at high speed. The mouse was grabbed directly, upon landing; in one instance, however, it disentangled from the bird’s foot and was captured after a few seconds. The target was usually grabbed at the shoulders or neck, or at the trunk. Soon after capture the kestrel flew to a distant perch, where it usually stroked the prey with one single peck, before starting ingestion, which began about 1 min time after prey grasping. Our results are the first to show the possibility of maintaining standardized conditions to study the predatory behaviour of birds of prey. As they are very similar to those obtained in previous tests carried out in captivity using rehabilitated kestrels, our results also confirm earlier ones showing that the kestrel’s predatory behaviour is rather stereotyped—i.e. performed with limited variation—and that it can be studied reliably even in captivity.     

Establishment of a free-ranging colony of stumptail macaques (Macaca arctoides): Social relations I

Data on the social behaviour of a free-ranging troop of Stumptail macaques are reported for a period starting of August 15th to November 7th of 1974. Positive interactions take a greater part in the daily life of the troop than negative interactions. Individuals order themselves in an essentially linear dominance hierarchy and offspring rank immediately below their mother. Agonism and displacement are good predictors of dominance rank. Dominant individuals are a strong source of attraction for subordinates and the alpha male is a powerful social magnet for immatures. Grooming was found to be correlated with dominance rank and individuals holding adjacent ranks tend to interact positively with one another. To gain access to dominant females, subordinates direct a great deal of positive behaviour to the female’s youngest offspring. As social distance decreases the selection of a social partner becomes more strict and tends toward adjacency. However, factors such as motherhood, genealogical ties, and special relationships with non adjacent individuals, can override the tendency. The direction and quantity of male-care displayed by the adult male and by juvenile males toward younger individuals was found to be influenced by the troop’s dominance patterns. Sex differences were found to exist in male-care received and a negative association was found with the age of the receiver. Adult females are the main regulators of social relations and their rank and friendships provide their offspring with the social format, before puberty, in which they develop socially. The alpha male is the group protector, the performer of policing, an important element in the immatures’ social development, and a powerful source of attraction for all troop members.