Styles of male social behavior and their endocrine correlates among high-ranking wild baboons

We have previously studied the relationship between dominance rank and physiology among male olive baboons (Papio anubis) living freely in a national park in Africa. In stable hierarchies, such males have distinctive secretory profiles of glucocorticoids and of testosterone. We find that these endocrine features are not, in fact, purely markers of social dominance; instead, they are found only among dominant males with particular stylistic traits of social behavior. One intercorrelated stylistic cluster revolved around the intensity with which the male is involved in sexual consortships (e.g., frequency of copulation, of grooming, degree to which feeding is suppressed by being in consortship). Males most involved in such consortships had the lowest basal cortisol concentrations and smaller cortisol stress-responses. A second stylistic cluster revolved around the degree of social affiliation (e.g., rate of grooming and interacting positively with non-estrus females and infants). Males who were highly affiliated had low basal cortisol concentrations and an attenuated cortisol stress-response. A third cluster revolved around the degree to which males could distinguish between highly threatening interactions with rivals and neutral or mildly threatening ones. Males most adept at this had lower basal cortisol concentrations. These behavioral/endocrine clusters were independent of each other. This suggests that the same adaptive physiological feature (e.g., low basal cortisol concentrations) may arise from different and independent personality styles. © 1992 Wiley-Liss, Inc.     

Play and social dynamics in a captive herd of gelada baboons (Theropithecus gelada)

Here, we provide quantitative data concerning adult and immature play distribution in geladas discussing the results in the light of their social dynamics. Sex differences in immature play does not seem to reflect sex differences in adult role; in fact, frequency, modality (C-play and LR-play), and motivation (measured by play initiations) to play did not vary according to the different sex-class combinations. The occurrence of adult-adult play suggests that geladas are characterized by an apparent more than actual rigidity in their social relationships and this is particularly evident in females which show peculiar traits in the use of social play. Specifically, adult females played with other adult females as much as with immature ones, thus suggesting their high motivation to engage in such interactions. This adult play behavioural pattern is typical of species showing relaxed/fluid more than despotic/rigid social relationships. Such assumption is also supported by the positive correlation observed between play and affinitive behaviours (grooming and agonistic support) found within each age-category (adult females and immature subjects). This evidence, together with the lack of correlation between aggressive contacts and social play, suggests that geladas use play for social assessment purposes and/or to increase their social affiliation levels.     

Social relationships and ritualized greetings in adult male baboons (Papio cynocephalus anubis)

Greetings involving exchanges of ritualized sexual gestures are a common form of interaction among adult male baboons, although relatively little attention has been paid to them. In this study, we investigate how greetings reflect important aspects of the male's social relationships, including dominance rank, age/residence status, and cooperative tendencies. The results are based on over 600 greetings among 12 adult males recorded during a 4-month study of a troop of wild olive baboons near Gilgil, Kenya. Four of the adult males were older, lower-ranking, long-term residents, which frequently formed coalitions to take estrous females away from the eight young, higher-ranking males. Virtually all dyads greeted: greetings occurred more than twice as often as other types of male-male interactions; and nearly all greetings occurred in a neutral context, in which there was no resource at stake. The percentage of greetings completed, the frequency with which different gestures were employed, and the roles adopted by each male varied significantly across old-old, old-young, and young-young dyads. Greetings between young adult males were often interrupted or actively resisted, consistent with their unstable and ambiguous dominance relationships. Greetings between old-old dyads were usually completed and appeared consistent with their cooperative relationships. One pair of old males formed a stable, reciprocal coalition against young males, and this pair's greetings showed remarkable symmetry of roles. Greetings, we hypothesize, function to allow males to negotiate important aspects of their relationships, including cooperation.     

Effect of testosterone and melatonin on social dominance and agonistic behavior in male Tscheskia triton

Social dominance and agonistic behavior play important roles in animal societies. Melatonin and testosterone are closely related to social dominance and agonistic behavior in rodents, but interactions between both of them remain unknown. In this study we investigated the effects of testosterone and melatonin by manipulating photoperiod and castration on social dominance and agonistic behavior in male Tscheskia triton. Castration significantly decreases social dominance of both short- and long-day males, suggesting that testosterone benefits social dominance of males in both breeding and non-breeding seasons. In intact conditions, long-day males tended to dominate short-day males, suggesting that the effect of testosterone on social dominance was a little stronger than melatonin. However, castrated short-day males became dominant over their castrated long-day opponents meaning that high melatonin levels obviously benefit social dominance in males. Hormone implantation indicated that testosterone had no effect on non-breeding condition, but that melatonin was important during the breeding season. Our results indicate that both testosterone and melatonin are important in determining social dominance in male hamsters, and the effect of testosterone appears to be stronger than melatonin. Testosterone is responsible for aggression and social dominance in male hamsters during the breeding season, while melatonin regulates behavior during non-breeding, probably due to the different seasonal secretory patterns of the hormones.     

Blood groups of baboons. Population genetics of feral animals

Blood and saliva from 495 Ethiopan baboons were collected in the field and tested for their human-type A-B-O groups while 493 blood samples were tested for their simian-type blood factors A^p, B^p, C^p, G^p, N^p, ca and hu. Four series of feral animals were tested: 194 olive baboons, a troop of 82 and another of 90 hamadryas baboons, and a series of 129 baboons classified as olive/hamadryas hybrids. In addition, 126 baboons from other sources were tested for their human-type A-B-O groups and 131 for their simian-type blood groups. Human-type groups A, B and AB but not group O were found in combined series of 621 animals. Gene frequency analysis also indicated the absence of group O. Population analysis of the data obtained for the 493 Ethiopian baboons has shown that the simian-type blood groups A^p and B^p are independent of one another. In contrast B^p and G^p appear to be determined by corresponding allelic genes; if confirmed by population data on additional series of animals, this would define the first baboon blood group system found. There is a close association between the blood group specificities ca and hu, the exact nature of which still remains to be clarified. Blood group ca, originally believed to be species specific, is found to be polymorphic in both olive baboons and hamadryas as well as in the hybrids; hu, on the other hand, present in all hamadryas tested, is polymorphic only in olive baboons.     

Scratching,dominance, tension,and displacement in male baboons

This paper reports a study designed to test the hypothesis that a relationship exists among dominance rank, tension, and scratch behaviors in anubis baboons (Papio cynocephalus anubis). Our study was conducted on two groups of male baboons, each containing eight unrelated individuals who were approximately 6 years of age and who shared common rearing histories. Focal animal sampling was used to collect behavioral data. Hand scratching, foot scratching, avoid, tension, allogrooming, autogrooming, and manipulation were measured as acts performed per hour of sampling. Dominance matrices were constructed based on net difference of avoid behavior performed and received (adjusted for time sampled). Individual status ranks were grouped into two status classes, high and low. Analysis of variance models demonstrated significant differences in the performance rate of scratching behaviors by dominance rank class, as well as differences in scratching performance by tension class. Individuals in the high status class had significantly higher rates of total scratching, hand scratching, foot scratching, and tension behavior performance than their counterparts in the low status class. No significant difference was found between status classes or tension classes for performance rate of allogrooming, autogrooming, or manipulation behavior. The frequency of scratching and general level of activity were not significantly correlated. The results are interpreted to indicate the possibility that scratching may function as a displacement behavior, which subjectively appears to communicate heightened frustration, anxiety, or arousal.     

Feeding behavior of yellow baboons (Papio cynocephalusin) the Amboseli National Park,Kenya

The results of an 11-month field study of the feeding behavior of adult yellow baboons (Papio cynocephalus)are presented. Although catholic feeders, the baboons are not unselective in their choice of foods, and a small number of foods account for the bulk of their feeding time and are significant determinants of their home-range utilization patterns. These preferred foods are consumed throughout the year, a response, perhaps, to relatively minor fluctuations in their availability. Seasonal changes in food abundance are, however, reflected in other aspects of the baboons’ feeding behavior, including a tendency to show greater day- to- day dietary variability during periods of higher rainfall and greater overall food availability. It is suggested that this, and other, aspects of baboon feeding behavior can be understood only in the context of the extremely “patchy” distribution of their food supplies.     

Aggression in adult male primates: A comparison of confined Japanese macaques and free-ranging olive baboons

The frequencies and types of adult male aggressive behavior of confined Japanese macaques (Macaca fuscata)and free-ranging olive baboons (Papio anubis)were compared. The baboons, which do not have a mating season, were more aggressive to conspecific males than were the macaques during their nonmating season. The baboons also solicited aid during aggressive encounters more frequently than the macaques. However, during their mating season, the macaques were more aggressive to conspecific females than were the baboons. The macaques were also involved in more triadic sequences of aggression, and the frequency of occurrence of these patterns supported Chase’s theory of dominance hierarchy formation and maintenance. The differences in aggressive behavior appeared to be related to the seasonal reproductive cycle of the macaques.     

The timing of ovulation with respect to sexual swelling detumescence in wild olive baboons

Baboon researchers commonly use the timing of sexual swelling detumescence to infer the timing of ovulation. These estimates are then used for a variety of purposes, including the interpretation of male and female behaviour, assessment of likely paternity, and the calculation of gestation lengths. Although captive studies have measured the timing of ovulation with respect to detumescence, this has not been measured in wild baboons. Here, we use observational data on female sexual swellings, and hormonal data measured from faeces, to investigate the timing of ovulation with respect to detumescence in wild olive baboons. Our data show similar variability in the timing of ovulation with respect to detumescence as that produced by captive studies, although there are some notable differences, including the absence of any ovulations measured on or after the day of swelling detumescence. We discuss the importance of our results for baboon researchers using swellings to infer ovulation as part of their studies.     

Ecological and social determinants of birth intervals in baboons

Birth rates in primates have long been proposed to result froman interaction between ecological and social factors. We analyzeda variety of social and environmental variables to determinewhich ones best explain the observed variation in interbirthintervals across 14 baboon populations. Both the number offemales in the group and mean annual temperature were foundto be important, and a multivariate equation containing thequadratic components of both these variables accounts for almostall the observed variance in interbirth intervals. The quadraticrelationship with temperature is explained in terms of theenergetic costs of maintaining a stable body temperature at both low and high temperatures. The quadratic relationship withnumber of females results from relationships with both foodavailability and the costs of increasing intragroup competitionas group size increases. Although females may be able to exerta certain degree of choice in their reproductive schedulingdecisions, they are ultimately constrained by limits imposedupon them by the complex interactions between their ecologicaland demographic environment.     

Intrasexual selection and male mating strategies in baboons and macaques

If baboon and macaque mating systems constitute a form of female defense polygyny, male mating strategies should be intrasexually selected and should vary in predictable ways with female defensibility, and demographic factors which affect the numbers of competing males per estrous female in populations. Substantial behavioral evidence exists for intrasexual selection of male mating strategies in baboons and macaques. Limited evidence also offers tentative support for theorybased predictions about the relationship between male mating strategy and female defensibility. Although male dominance rank generally predicts mating success, there are a number of factors which tend to increase the success of subordinate males above that expected from a simple dominance-based model of priority of access to mates.     

The social contingency model and olive baboons

A theoretical and illustrative analysis of sequences of actions between pairs of olive baboons (Papio cynocephals anubis) is carried out using the social contingency model originally suggested by Jones and Gerard (1967) in social psychology. The model provides the basis for a step-by-step analysis and a typology. Signals from body postures, facial expressions, and vocalizations are subject to close study by using the model, in a similar fashion to its use in social skills analysis (Argyle, 1988). Sequences are categorized according to individual and joint strategies. Examples are given of three categories of contingency, reactive, mutual, and asymmetrical, which are adapted from their social psychological usage. The model is extended by a new category for competitive relationships between baboons: a conflictive category. The contingencies, as they are shown graphically, have a superficial resemblance to Tinbergen's (1951) zigzag diagrams, but their purpose is distinct in focusing on the detail of both infrequent and repeated interactions. The overall aim of the contingencies is to improve the analysis of social behavior at the proximate level and the model is potentially applicable to observation records at a level of detail that is often not utilized in reporting field studies.     

The reproductive behavior of the longspine snipefish,Macrorhamphosus scolopax (Syngnathiformes,Macrorhamphosidae)

Synopsis About two hundred Macrorhamphosus scolopax were observed in a large tank and their behavior was videotaped for subsequent analysis. When not disturbed, the fish moved slowly in a head-down position. Spawning in the tank took place in the last two hours before dark. Courting males change color and actively interact aggressively with other males. They push against each other while swimming in parallel or they charge their opponents with their erected dorsal spine directed at them. Courtship begins near the bottom. After following and swimming parallel to the female the two fish unite tightly by their caudal peduncle, with their ventral regions in close proximity and rise slowly in the water column. During the ascent, the genital papilla of the female extends repeatedly and contacts the genital region of the male.     

Patterns of reconciliation among captive gelada baboons (Theropithecus gelada): A brief report

Animals that live in groups are frequently exposed to conflict situations and must in some way maintain group cohesion. One mechanism that appears to restore social relationships after they have been disrupted by conflict isreconciliation. This study investigated reconciliatory behavior in the gelada baboon,Theropithecus gelada. The subjects were 11 adult geladas, housed in a large outdoor enclosure at the Bronx Zoo/Wildlife Conservation Park, New York. Five-minute focal animal samples following spontaneous aggression were compared with 5-min matched-control samples. The results of this study were: (1) geladas reunited in a friendly way after aggression; (2) former opponents were attracted to one another rather than dispersed from one another after a conflict; (3) most post-conflict reunions occurred within the first 2 min of the post-conflict period; and (4) geladas do not have any specific types of behavior associated with post-conflict reunions as do chimpanzees and macaques. The results of this study support the hypothesis that gelada baboons reconcile after aggression.     

The benefits of social capital: close social bonds among female baboons enhance offspring survival

Sociality has evolved in many animal taxa, but primates are unusual because they establish highly differentiated bonds with other group members. Such bonds are particularly pronounced among females in species like baboons, with female philopatry and male dispersal. These relationships seem to confer a number of short-term benefits on females, and sociality enhances infant survival in some populations. However, the long-term consequences of social bonds among adult females have not been well established. Here we provide the first direct evidence that social relationships among female baboons convey fitness benefits. In a group of free-ranging baboons, Papio cynocephalus ursinus, the offspring of females who formed strong social bonds with other females lived significantly longer than the offspring of females who formed weaker social bonds. These survival benefits were independent of maternal dominance rank and number of kin and extended into offspring adulthood. In particular, females who formed stronger bonds with their mothers and adult daughters experienced higher offspring survival rates than females who formed weaker bonds. For females lacking mothers or adult daughters, offspring survival was closely linked to bonds between maternal sisters. These results parallel those from human studies, which show that greater social integration is generally associated with reduced mortality and better physical and mental health, particularly for women.     

The influence of social experience on the behavior of male cockroaches,Nauphoeta cinerea

The influence of social experience on rates of agonistic behavior was investigated in a cockroach, Nauphoeta cinerea. Social experience was manipulated by establishing three types of groups of four identically aged males: (1) ran-domly chosen, socially naive males (control); (2) males of similar status and activity level (from treatment 1); and (3) males returned to their original hierarchy after experiencing treatment 2. In the control groups, we found stable hierarchies, significant differences in the rate of agonistic behaviors exhibited among different status males, and a significant relationship between social status and level of agonism. We also compare activity levels within and among groups after males had novel social experiences. Among similar status individuals, we found less activity than when they wereintheir original groups. When males were returned to their original groups, the level of activity increased compared to the level of activity before treatment. The social status of males was unstable after these treatments. Losing tended to result in relatively more subordinate behavior, and winning in relatively more dominant behavior by a male. Within groups, the rate of agonism also increased over 5 days in groups of males that had no previous interactions with each other, while the rate of agonism remained the same in groups of familiar males. We interpret these results in light of male-male assessment and the maintenance of social status in this species.     

Proximate and ultimate causes of reproductive suppression among female yellow baboons at Mikumi National Park,Tanzania

Attack coalitions, whereby two or more individuals attack another animal simultaneously, were studied in 53 sexually mature female baboons from one small and two large troops at Mikumi National Park, Tanzania. For 14 months, three observers recorded coalition behavior throughout the day, using focal group sampling on a behavior-dependent basis. Coalition rates were considerably greater in the two large troops than in the small troop, and primarily involved natal females rather than males. Coalition frequencies corresponded closely to measures of reproductive synchrony, both within and between troops. Involvement in attack coalition behavior depended on the reproductive states and ranks of both attackers and recipients. The first few females to give birth in the cohort received particularly high amounts of coalition aggression just before and immediately after giving birth. Receipt of attack coalitions was significantly associated with an increased number of cycles to conception and longer interbirth intervals, as well spontaneous abortion, premature birth, and prolonged gestation. A parallel study on survivorship patterns of immature baboons at Mikumi provided evidence for ultimate cause of the observed coalition patterns. These combined results suggest that attack coalition behavior is a form of reproductive competition whereby females attempt to suppress the reproduction of others at predictably competitive times and thereby reduce the competition their own infants face from the time they are weaned.