Dominance relationships among male hamadryas baboons (Papio hamadryas)

The concept of dominance has been shown to be useful in describing and predicting social interactions in group-living animals. However, the dominance relationships among adult hamadryas males (Papio hamadryas) are poorly understood, and systematic data are missing from the literature. This study investigated dominance relationships among male hamadryas baboons by applying novel statistical techniques to systematic detailed data on agonistic interactions. We also analyzed the dominance relationship with male age and evaluated the association between dominance and access to mating partners (i.e. the number of adult females per one-male unit (OMU)), food resources (i.e. monopolization of feeding areas), and greeting interactions. The derived dominance indexes showed that, in general, leader males were dominant over followers, and that dominance ability did not correlate with male age. Individual dominance values were very close to each other, suggesting that dominance relationships among hamadryas males were not very rigid. In addition, dominance values were positively correlated with number of adult females per OMU but not with feeding priority. Finally, greeting interactions occurred more frequently between individuals with similar dominance values and with low levels of dominance decidedness. We suggest the need of further studies, especially in wild populations, to confirm our findings.     

Environmental variation and developmental rate among free ranging yellow baboons (Papio cynocephalus)

Behavioral development was observed for the first 3 months of life on 18 infants from three troops of yellow balloons (Papio cynocephalus) in Mikumi National Park, Tanzania. Developmental rates were determined for each subject on six major behaviors using the slope from regression equations performed on developmental functions changes in behavior with age. These slopes were examined statistically for associations with social and physical variables that were hypothesized to influence developmental rates. Results showed that faster rates of development were significantly associated with certain environmental and social conditions. Infants born late in their cohort, infants born in a more physically immature state, infants living in a large troop, and female infants of low ranking mothers all had significantly faster rates of development than infants at the other extreme in these categories. These results are interpreted as evidence for developmental processes that compensate for environmental or physical conditions that negatively influence survivorship. © 1995 Wiley-Liss, Inc.     

The order of movement of yellow baboons (Papio cynocephalus).

The spatial organization of progressing baboons is thought to serve a protective function considered important in their adaptation to a terrestrial existence. Progression positions of identified black infants, adult males, and other yellow baboons were determined from repeated samples of troop movements. Spatial positioning by demographic class was similar to that previously found for three troops of anubis baboons living in two different habitats. Such consistency across species and habitats seems unlikely unless it arises from a common genetic background or common ontogenetic stabilizing mechanism.     

Nuclear DNA polymorphisms in a wild population of yellow baboons (Papio hamadryas cynocephalus) from Mikumi National Park,Tanzania

Yellow baboons (Papio hamadryas cynocephalus) from Mikumi National Park, Tanzania were studied for polymorphisms in nuclear DNA. The study population consists of four social groups that inhabit overlapping home ranges and exchange males. As a result, these groups are considered to be members of a single interbreeding population. Human DNA clones were used as probes to screen five loci (AT3, REN, HEXB, VIM, and APOB) for restriction fragment length polymorphisms (RFLP). A total of 14 polymorphisms, at least one at each locus, was detected in a panel of 27 baboons tested using six restriction enzymes for each locus. Eleven of these RFLP systems have average heterozygosity values greater than 0.40. This initial screening demonstrates that human DNA clones can be used to detect significant numbers of informative DNA polymorphisms in single-copy nuclear genes of this species and suggests that the average proportion of nucleotides polymorphic across nuclear loci in this population may be between 1.0% and 1.3%. © 1993 Wiley-Liss, Inc.     

Low Y chromosome variation in Saudi-Arabian hamadryas baboons (Papio hamadryas hamadryas)

It is important to characterise the amount of variation on the mammalian Y chromosome in order to assess its potential for use in evolutionary studies. We report very low levels of polymorphism on the Y chromosome of Saudi-Arabian hamadryas baboons, Papio hamadryas hamadryas. We found no segregating sites on the Y, despite sequence analysis of 3 kb noncontiguous intron sequence in 16 males with divergent autosomal microsatellite genotypes, and a further analysis of 1.1 kb intron sequence in 97 males from four populations by SSCP. In addition, we tested seven human-derived Y-linked microsatellites in baboons. Only four of these loci were male-specific and only one was polymorphic in our 97 male sample set. Polymorphism on the Y chromosome of Arabian hamadryas appears to be low compared to other primate species for which data are available (eg humans, chimpanzees and bonobos). Low effective population size (Ne) of paternal genes due to polygyny and female-biased adult sex ratio is a potential reason for low Y chromosome variation in this species. However, low Ne for the Y should be counterbalanced to some extent by the species' atypical pattern of male philopatry and female-biased dispersal. Allelic richness averaged over seven loci was not significantly different between an African and an Arabian population, suggesting that loss of variation during the colonisation of Arabia does not explain low Y variation. Finally, in the absence of nucleotide polymorphism, it is unclear to what extent selection could be responsible for low Y variation in this species.     

Allogrooming and social status: An assessment of the contributions of female behavior to the social organization of hamadryas baboons (Papio hamadryas)

Three isosexual social groups, each containing ten subadult female hamadryas monkeys (Papio hamadryas) were studied for seven months to test three hypotheses dealing with the assumptions underlyingSeyfarth's (1977) model of allogrooming and social organization. Aggression, avoid and allogrooming behaviors were used as criteria for studying the social organization of the groups. UsingLandau's (1951) index and discriminant analyses, we found that each of the three isosexual female social units conformed to a model of social organization having a non-linear hierarchy and only two major strata: a dominant animal and subordinates who were largely undifferentiated. This aspect of social organization is similar to the normal one-male unit leader harem form of social organization that is typical of hamadryas. However, since no male was present, the role of unit leader was filled by a female. The length of allogrooming bouts and the amount of allogroom received was affected by the social status of the recipient, with high status individuals receiving more than low status individuals. Social peers were not observed competing for access to high status individuals and did not exchange most of their grooming among themselves. We found that the assumptions underlyingSeyfarth's (1977) model were not appropriate for the type of social organization typically found in hamadryas monkeys, thus suggesting the need for further modification of the model so that it fits available data.     

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.     

Pasteurella multocida infections in baboons (Papio cynocephalus)

The respiratory pathogenPasteurella multocida was isolated from infections of the laryngeal air sacs of two baboons and from abscesses in the neck or femoral area of two other baboons. The infections were associated with surgical procedures involving the cervical area, chronic catheterization, and chair restraint. The organism was also detected among the commensal pharyngeal flora in 2 of 15 clinically healthy, wildborn adult baboons. These findings suggest that the organism is harbored naturally in baboons and that exudative infections can occur secondary to specific procedures.     

Sparganosis in wild-caught baboons (Papio cynocephalus anubis)

BACKGROUND: Sparganosis is the infection of a paratenic host with the plerocercoid metacestode of Spirometra spp. A 12-year-old captive, pregnant, wild-caught baboon from Tanzania had multiple subcutaneous nodules. METHODS: Examination of the biopsied nodules revealed the presence of viable metacestodes. The histological morphology of the metacestodes was consistent with the genus Spirometra and other pseudophyllidean cestodes. Since species of Spirometra produce growth hormones that are active in mammals, we measured fetal and placental growth and hormone levels. Blood samples were taken from the mother and the cesarean-derived fetus for hematological, biochemical, and hormonal analyses and to test for the presence of antispargana antibodies. RESULTS: Baboon placental weight and fetal hematological, biochemical, and morphometric parameters were within normal ranges. Antibody titers to spargana did not differ significantly between mother (1.08 OD(405)) and fetus (0.91 OD(405)). Baboon maternal insulin-like growth factor and growth hormone values were also within the normal range. Estradiol and progesterone analysis in four of these animals (antibody titers ranged from 0.71 to 1.7 OD(405)) showed no statistically significant difference with age- or phase-matched cycle parameters compared with antibody-negative females. CONCLUSIONS: Based on the results that have been obtained, sparganosis did not appear to affect the endocrinological profile of pregnant and cycling female baboons.     

Palatal growth in baboons (Papio cynocephalus anubis)

In this study the structure and development of the palate as observed in a cross-sectional collection of olive baboons (Papio cynocephalus anubis) skulls are described and analyzed using craniometric techniques. Considered are structural functional relationships among different parts of the palate, and between the palate and other parts of the craniofacial skeleton. Several inferences are drawn and speculated upon. These inferences are as follows: odontogenesis affects premaxillary growth the most during late fetal and early postnatal development; maxillary length is significantly affected by development and eruption of the maxillary dentition, whereas maxillary breadth is less affected by dental development. Growth of the palatine bones and nasopharyngeal airway is correlated with dentomasticatory changes; the developmental and functional significance of these correlations is unclear. Further inferences are that growth rates for each palatal component differ for each sex even though lengths of the components relative to total palatal dimensions show no sexual dimorphism. Also, it is determined that maxillary length remains constant, premaxillary length reduces and palatine length increases relative to total palatal length with growth.     

Tail carriage in baboons (Papio cynocephalus): relationship to dominance rank and age.

Several metric and categorical variables were used to assess tail carriage in 717 photographs of 54 yellow baboons (Papio cynocephalus) of known identity, sex, dominance rank, and estimated or known age. Analyses of these data demonstrated that age was the primary factor, influencing tail carriage of baboons not engaged in social interaction. Specifically, the proximal segment of the tail was carried increasingly close to the vertical with increasing age; other changes in tail angles and segment curvature were also correlated with age. There was no relationship between dominance rank and neutral tail carriage in adult male or female baboons, nor was the neutral tail carriage of the first-ranking male or female either distinctive or characteristic. The morphological basis of ontogenetic changes in neutral tail carriage in baboons is also discussed.     

The effect of medroxyprogesterone acetate on behavioural responses of captive female hamadryas baboons (Papio hamadryas)

Female hormonal contraception is considered here as an alternative to vasectomy for population control in social groups of captive hamadryas baboons (Papio hamadryas). While female hormonal contraceptive methods have been successful, behavioural effects of such agents represent a potential welfare concern. This study examined the effect of medroxyprogesterone acetate (MPA; 3.5 mg/kg) on perineal tumescence and behaviour in three social groups (total of 3 males, 22 females) of captive hamadryas baboons. The agent had little effect on social interactions such as grooming relationships, aggression and affiliation (all P > 0.05), but did cause a reduction in sexual behaviour (P < 0.001). Females-mounting-females and females receiving mounting was decreased during MPA treatment compared with the minimal tumescence phase (P < 0.001). Age strongly influenced the contraceptive's duration: there was a significant correlation between age and latency of return to oestrus post-MPA (r = 0.832, P < 0.001) with the latency increasing by 2.61 days per year of age on average. Age also influenced the frequency of behaviours such as affiliation and aggression (P < 0.001 and P = 0.044, respectively). The absence of adverse behavioural effects further supports the use of MPA in the hamadryas baboon, and its potential use in other non-human primates.     

Social stressors and coping mechanisms in wild female baboons (Papio hamadryas ursinus)

We examined the social correlates of fecal glucocorticoid (GC) levels in wild female baboons during a period of social and demographic stability. Females' GC levels were not affected by individual attributes such as number of kin or dominance rank, nor could we detect any significant seasonal effects. Instead, GC levels were influenced by behavioral attributes that varied between individuals and within individuals across time. Pregnant and cycling females who received high rates of aggression had higher GC levels than others. In contrast, pregnant and cycling females who received grunts - vocal signals of benign intent - at high frequencies from dominant females had lower GC levels than females who received grunts at lower frequencies. Lactating females showed the opposite trend, apparently as a consequence of the high rate of grunting and intense, unsolicited attention that their infants received from others. All females experienced lower GC levels in months when they concentrated their grooming among a small number of partners than when their grooming was more evenly distributed among many partners. Although GC levels in female baboons are most strongly influenced by events that directly affect their reproductive success, subtle social factors associated with the loss of predictability and control also seem to exert an effect. Loss of control may be mitigated if a female is able to predict others' intentions - for example, if others grunt to her to signal their intentions - and if she is able to express some preference over the timing and identities of her grooming partners.     

Movement patterns of yellow baboons (Papio cynocephalus): Central positioning of walking infants

According to DeVore and Washburn's protection theory of the spatial organization of moving baboon troops, walking infants, which are among the most vulnerable and least self-sufficient of all troop members, should tend to occupy the troop's center. The protection theory is an ultimate hypothesis from which persistently recurring behavior is expected. Two troops living in Mikumi National Park, Tanzania, were compared with troops studied at other locations. Walking infants tended to occupy the center of their troop and to be underrepresented primarily in the frontal portion of progressions and secondarily in the rear. The lead position of progressions was analyzed using 82 walking infants, 11 troops, three locations, two species, and three studies involving eight or more observers employing somewhat different procedures at the different study sites. Despite so many opportunities for variation, 1,317 observations from these 11 troops did not produce a single instance in which a walking infant led the troop and very few in which one was in the frontal twelfth.     

Hemoglobins of baboons, Papio cynocephalus, P. gelada and P. hamadryas

Major hemoglobins of adult Papio cynocephalus, P. gelada, and P. hamadryas and of newborn P. cynocephalus were purified; globins were prepared; and α and β or α and γ chains were separated. The amino acid compositions and aminoterminal groups were determined. These were compared with analogous data for human hemoglobins, other baboon hemoglobins and macaque hemoglobins.     

Reconciliation in hamadryas baboons, Papio hamadryas: testing the relationships quality hypothesis

Post-conflict interactions between former opponents were investigated in a troop of hamadryas baboons, Papio hamadryas. This species is known for it's multilevel structure with evidently expressed hierarchy between males and females. Due to this fact hamadryas baboons represent an ideal object for testing the "relationship quality" hypothesis. The analyses were done on 436 PC-MC pairs of animals, which represented different social classes (harem male-female pairs, harem females, relatives, females from different harems. Male-male pairs, and female-subadult pairs). Reconciliation was practiced in different social classes of individuals: harem male-female pairs, harem female-female pairs, kin-kin pairs, male-male pairs, female-subadult pairs. Significant differences in the rate of reconciliatory tendency for different categories of interacting animals were found. Interactions between former opponents were highly selective. These may be interpreted as an indicator of the influence of the relation quality on the probability of reconciliation in hamadryas baboons.     

Osteopenia and osteoporosis in adult baboons (Papio hamadryas)

BACKGROUND: Little is known about the degree to which baboons, an important animal model in skeletal research, spontaneously experience age-related osteopenia and osteoporosis. METHODS: We measured bone mineral density (BMD) in 667 baboons, assigned T-scores to older animals based on sex-specific young adult reference groups, and compared reproductive history in older females with low BMD to those with normal BMD. RESULTS: Approximately 25% of older baboon females were osteopenic. No females or males were osteoporotic. Neither parity nor interbirth interval spine clearly distinguished low vs. normal BMD groups. Intersite correspondence in low BMD was highest between sites in the same region rather than sites of the same bone type. CONCLUSION: As with humans, osteopenia is common among older females. The absence of osteoporotic animals may be due to colony maintenance resulting in truncation of the aged population and selection for healthier animals in the oldest ranges.     

Behavioural and hormonal responses to predation in female chacma baboons (Papio hamadryas ursinus)

In humans, bereavement is associated with an increase in glucocorticoid (GC) levels, though this increase can be mitigated by social support. We examined faecal GC levels and grooming behaviour of free-ranging female baboons to determine whether similar effects were also evident in a non-human species. Females who lost a close relative experienced a significant increase in GC levels in the weeks following their relative's death compared with the weeks before, whereas control females showed no such increase. Despite the fact that females concentrate much of their grooming on close kin, females who lost a close female relative did not experience a decrease in grooming rate and number of grooming partners; instead, both grooming rate and number of grooming partners increased after a relative's death. While the death of a close relative was clearly stressful over the short term, females appeared to compensate for this loss by broadening and strengthening their grooming networks. Perhaps as a result, females' GC levels soon returned to baseline. Even in the presence of familiar troop-mates and other relatives, females experienced a stress response when they lost specific companions, and they apparently sought to alleviate it by broadening and strengthening their social relationships.