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.     

Cranial ontogeny of Papio baboons (Papio hamadryas)

Cranial form in subspecies of Papio baboons (Papio hamadryas) varies in relation to size, geography, and sex. However, knowledge about this variation is based mainly on adults, precluding direct assessments of the evolutionary factors that are ultimately responsible for adult shape variation. Consequently, this study tests hypotheses about the development of size and shape differences among subspecies of Papio baboons, anticipating limited evolutionary divergences in the ontogenetic pathways leading to adult endpoints. Geometric morphometric and bivariate allometric analyses are used to explore developmental size and shape variation. Allometric scaling in adult Papio baboons occurs because both sexes and all subspecies follow similar developmental pathways to a variety of adult forms. However, complex allometry contributes to form differences, producing potentially important shape differences that emerge during development. Modest shape differences that are statistically independent of size distinguish chacma baboons (P. h. ursinus) from other forms. A small-headed subspecies, the Kinda baboon (P. h. kindae), also presents a distinctive ontogeny, and may provide insights into the evolution of size change in this species. Variation among subspecies that is statistically independent of size involves the rostrum, zygomatic breadths, and cranial flexion. These features may be related to diet, but the precise biomechanical correlates of baboon form variation remain unclear.     

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.     

Ranging behavior,group size and behavioral flexibility in Ethiopian hamadryas baboons (Papio hamadryas hamadryas)

This study reports group size, home range size, daily path lengths, seasonal effects on ranging behavior and qualitative information on diet for a population of hamadryas baboons inhabiting the lowlands of the northern Rift Valley in central Ethiopia. The minimum home range size and daily path length for this population are similar to those reported for other populations of hamadryas baboons in Ethiopia and Saudi Arabia. Group sizes, however, are much larger than those in most other hamadryas populations for which published data are available. The large group sizes in this area may be related to the abundance of one food resource in particular, doum palm nuts. Overall, this study suggests that hamadryas baboons may be more flexible in some aspects of their behavioral ecology (e.g. group size) than in others (e.g. ranging behavior).     

Early sexual maturity in male hamadryas baboons (Papio hamadryas hamadryas) and its reproductive implications

We present data on sexual maturity in young hamadryas baboon males (Papio hamadryas hamadryas) and its reproductive consequences in a large captive baboon colony. Hamadryas baboons live in a multilevel social system, with one-male units (OMUs) as the smallest social entity. Male leaders of OMUs are believed to monopolize matings within their OMUs; hence mating is believed to be polygynous and monandrous. In a captive colony of hamadryas baboons, we found evidence that young males less than 4 years old fathered at least 2.5% of 121 offspring born subsequent to vasectomy of all adult males, and males aged 4-5 years fathered at least 16.5% of the offspring. Additional evidence that these young males are able to sire offspring came from a morphological comparison of sperm from hamadryas males of different ages. The sperm of a 48-month-old hamadryas baboon were morphologically indistinguishable from viable sperm from adult males, whereas sperm from a 45-month-old male showed some aberrations. If successful copulations by adolescent males constitute a regular pattern even in free-ranging hamadryas baboons, a hamadryas male's chances to reproduce would not be limited to his role as an OMU leader as previously assumed, and a male's reproductive career would consist of two phases: the adolescent phase, and the OMU leader male phase.     

Testing the function of reconciliation and third-party affiliation for aggressors in hamadryas baboons (Papio hamadryas hamadryas)

In social groups, agonistic conflicts can have different negative consequences. Several post-conflict interactions have been suggested as post-conflict management behaviors to mitigate those negative effects. In this study, we investigated the function of two post-conflict behaviors--reconciliation and aggressor-initiated third-party affiliation--on the aggressor's levels of post-conflict anxiety and aggression in a large colony of hamadryas baboons. We also examined variation in the aggressor's levels of post-conflict anxiety as a function of relationship quality between the opponents as predicted by the Integrated Hypothesis. We found that after conflicts hamadryas baboon aggressors showed increased rates of anxiety-related behaviors and that they were also more likely to be involved in renewed aggressive interactions. Although both reconciliation and aggressor-initiated third-party affiliation reduced the probability of receiving post-conflict aggression, only reconciliation reduced the rates of anxiety-related behaviors, suggesting that the aggressors' post-conflict anxiety might be owing mainly to the damage that the conflict causes to their relationship with the victim. Furthermore, aggressor's rates of post-conflict anxiety were higher after conflicts with individuals with whom they had a high-quality relationship, supporting the idea that levels of post-conflict anxiety mediate the occurrence of reconciliation depending on the quality of the relationship with former opponent as predicted by the Integrated Hypothesis.     

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.     

Testicular endocrine function in hamadryas baboons (Papio hamadryas) during chronic emotional stress

Radioimmunoassay was applied to examine the time course of blood plasma testosterone content in 10 adult male hamadryas baboons under repeated immobilization stress (IS). In the first series of experiments, the monkeys (5) were subjected to daily IS for 2 h during 6 days. In the second series, 5 animals were exposed to 2-hour immobilization 3 days prior to the analogous stressful cycle. In response to intermittent IS the first series males demonstrated profound and long-term suppression of blood testosterone that persisted for 2 days after IS cessation. Preliminary application of a stressful stimulus substantially reduced the degree of blood testosterone suppression. Transitory decrease in blood testosterone was observed 2 hours after the outset of each stressful exposure, followed by complete recovery of testosterone blood level after 6 hours. The differences in the time course of testosterone indicate that the response of the pituitary-gonadal system is dependent on the regimen of stressful stimulus application.     

Use of palm trees as a sleeping site for hamadryas baboons (Papio hamadryas hamadryas) in Ethiopia

Hamadryas baboons sleep on cliffs throughout their range, and this can be attributed to the safety cliffs provide against predators in the absence of tall trees. In this paper, we report the first documented occurrence of hamadryas baboons sleeping in doum palm trees rather than on cliffs. Data derive from a study of hamadryas baboons at the Filoha site in lowland Ethiopia. During all-day follows, data were collected on travel patterns, band activity, and location. Variation in the baboons' home range was characterized using vegetation transects. We discovered that one band in this population, Band 3, occasionally slept in doum palm trees (Hyphaene thebaica). The palm tree sleeping site differed from other palm fragments in the baboons' home range in that it contained a higher density of palm trees. Possible factors influencing this unique use of palm trees as a sleeping site include access to palm fruit, avoiding contact with Afar nomads, avoiding sharing sleeping cliffs with other bands, protection from predators, and the lack of cliffs in a section of the baboons' home range. Evidence from this study suggests that the palm tree sleeping site is used because it affords better protection from predators than other palm fragments in an area of the band's home range that does not contain cliffs.     

Hematology and blood biochemistry in infant baboons (Papio hamadryas)

Although published normative reference standards for hematologic and clinical chemistry measures are available for adult baboons, their applicability to infants has not been addressed. We analyzed these measures in 110 infant baboons (55 females and 55 males) from a large breeding colony at the Southwest Regional Primate Research Center in San Antonio, Texas. The sample consists of olive baboons and olive/yellow baboon hybrids, 1 week to 12 months of age. We produced cross-sectional reference values and examined the effects of age, sex, and subspecies on these variables. Hematology reference ranges for infant baboons are similar to, but wider than, those for adults. Reference ranges for blood biochemistry measures are generally more dissimilar to adults, indicating that for many variables, reference ranges for adult baboons are not adequate for infants. Although sex and subspecies differences are rare, age accounts for more than 10% of the variance in many of the variables.     

Verreaux's eagles (Aquila verreauxi) as potential predators of hamadryas baboons (Papio hamadryas hamadryas) in Eritrea

In this paper we describe for the first time encounters of Verreaux's eagle (Aquila verreauxi) with hamadryas baboons (Papio hamadryas hamadryas) in the central highlands of Eritrea (15° 22′ N, 38° 58′ E, 2300 m). During 12 h of observation on 4 days, we observed four encounters of Verreaux's eagles with baboons, of which three can be classified as possible attacks. The baboons always responded with alarm calls. In three cases some immatures rushed to adult group members and clung to them, particularly to the adult male. Adult males threatened the eagle, and the whole group did not flee. The response of baboons towards smaller raptors like tawny eagles (Aquila rapax) and black kites (Milvus migrans) was very different. The adult baboons gave no alarm barks but scanned the raptors. The permanent presence of a pair of Verreaux's eagles in the home range of the baboons may represent a considerable predation pressure, at least for immature baboons. Am. J. Primatol. 47:61–66, 1999. © 1999 Wiley‐Liss, Inc.     

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.     

Effect of immobilization stress on the gonadotropic function of the hypophysis in male hamadryas baboons (Papio hamadryas)

The plasma levels of luteinizing hormone (LH) and testosterone were studied in intact and castrated male baboons exposed to 2- and 10-hour periods of immobilization. Presented data have shown that immobilization stress induced a marked decrease in LH concentration both in intact and castrated monkeys. Changes in LH concentration positively correlated with plasma levels of testosterone only during the experimental procedures. During three days after immobilization there was a sharp dissociation in the dynamics of testosterone levels remained low and LH returned to normal values. We can suggest that it is not absolute LH level that is responsible for the changes in testosterone secretion during the immobilization stress.     

Reproductive and neonatal outcomes in captive bred baboons (Papio hamadryas)

Abstract: Baboons are widely used in biomedical research. Although it is widely held that Papio hamadryas breed well in captivity, each established colony has a different reproductive success often hypothesised to be due to husbandry practices. The National Baboon Colony in Australia is a unique colony that houses Papio hamadryas to mimic that structure seen in the wild. In this article; we have analysed their reproductive parameters and neonatal outcomes. The success of the colony husbandry practices was demonstrated by lack of maternal mortality, low foetal morbidity, and known maternal and paternal linage.     

Grooming and group structure in hamadryas baboons

The results of 3-year observation on coral living hamadryas baboons transported from natural habitat in Tuapse reservation have been presented. Despite of the fact that grooming between males and females accounted for 73% of total cases of grooming in adult individual pairs, only the relationships of males with high-ranked females of their harems fully corresponded to a star-shaped sociogram. The high-ranked females were not different from all the other females either according to a total number of grooming cases with their female partners or according to a proportion of a performed and received grooming. Grooming between the related females was noted predominantly in the cases when they belonged to the same harem. Grooming between the related males accounted for 59% of all the cases of grooming between the male partners.