Tracking dietary transitions in weanling baboons (Papio hamadryas anubis) using strontium/calcium ratios in enamel

Strontium and calcium are incorporated into developing teeth in a manner that reflects changing physiological concentrations in the body. A new model predicts changes in strontium/calcium (Sr/Ca) ratios in response to dietary transitions experienced at birth and during the weaning period. Microsampling of longitudinal thin sections of tooth enamel using laser ablation inductively coupled plasma mass spectrometry provides a basis for the systematic evaluation of variation in Sr/Ca ratios within the tooth crown. Incremental growth markers in enamel are used to determine the age of onset of enamel mineralization at each sampling point. Thin sections of 5 teeth from 2 wild-caught baboons (Papio hamadryas anubis) were systematically analysed using this technique. Intra- and intertooth analyses of Sr/Ca ratios reveal a pattern of dietary development during the period of enamel formation that is consistent with observational data on the timing of weaning behaviour in anubis 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.     

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.     

Hormonal correlates of ontogeny in baboons (Papio hamadryas anubis) and mangabeys (Cercocebus atys)

This study investigates the relationship between serum hormone levels and morphometrics during ontogeny in olive baboons (Papio hamadryas anubis) and sooty mangabeys (Cercocebus atys), to test hypotheses about the endocrine regulation of species size differences. First, we expect that levels of hormones and binding proteins predict size change during ontogeny in both species. Second, a high level of integration among the hormones and binding proteins analyzed is expected, with the implication that they act in combination to influence the development of body size and shape. Utilizing a mixed longitudinal sample, we compare change in 18 different measurements, which reflect overall size growth as well as growth in length and circumference, with levels of six growth-related hormones and binding proteins. We examine the relationship between hormone and binding protein levels and morphometrics, using multivariate analyses and "arithmetically-estimated" velocity curves of hormones, binding proteins, to characterize how the endocrine factors analyzed relate to growth. Results suggest that levels of these endocrine factors can be used to predict local and overall growth during ontogeny and that integration between multiple hormone axes is indicated. While important for growth in both species, ontogenetic changes in hormone and binding protein levels are more tightly correlated with changes in morphometric measurements in baboons than mangabeys. These results have important implications for understanding why some smaller-bodied species have higher absolute growth-related hormone levels than larger-bodied species.     

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.     

Complete rectal prolapse in wild anubis baboons (Papio anubis)

This report describes two cases of rectal prolapse in wild anubis baboons (Papio anubis), with one spontaneous resolution. Both occurred after individuals consumed low‐water, high‐fibre dried maize during provisioning prior to capture, while one also experienced distress during capture.     

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.     

Behavioral variation and reproductive success of male baboons (Papio anubis x Papio hamadryas) in a hybrid social group

We take advantage of an array of hybrid baboons (Papio anubis x Papio hamadryas) living in the same social group to explore the causes and consequences of different male mating strategies. Male hamadryas hold one-male units and exhibit a sustained, intense interest in adult females, regardless of the latter's reproductive state. Anubis baboons, by contrast, live in multi-male, multi-female groups where males compete for females only when the latter are estrous. These two taxa interbreed to form a hybrid zone in the Awash National Park, Ethiopia, where previous work has suggested that hybrid males have intermediate and ineffective behavior. Here, we first examine male mating strategies with respect to morphological and genetic measures of ancestry. We found significant relationships between behavioral measures and morphology; males with more hamadryas-like morphology had more hamadryas-like behavior. However, genetic ancestry was not related to behavior, and in both cases intermediates displayed a previously unreported level of behavioral variation. Furthermore, male behavior was unrelated to natal group. Second, we evaluated reproductive success by microsatellite-based paternity testing. The highest reproductive success was found for individuals exhibiting intermediate behaviors. Moreover, over nine years, some genetically and morphologically intermediate males had high reproductive success. We conclude that the behavior of hybrid males is therefore unlikely to be an absolute barrier to admixture in the region.     

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.     

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.     

Trisomy of chromosome 18 in the baboon (Papio hamadryas anubis)

Trisomy 18 is usually a lethal chromosomal abnormality and is the second most common autosomal trisomy in humans, with an incidence of 1:8000 live births. It is commonly associated with abnormalities of the lower and upper extremities, having the frequency of 95% and 65%, respectively. A newborn female olive baboon (Papio hamadryas anubis) was diagnosed with intrauterine growth retardation and severe arthrogryposis-like congenital joint deformities. Cytogenetic analysis including G-banding and fluorescence in situ hybridization (FISH) revealed that the congenital abnormalities were associated with chromosomal mosaicism for trisomy 18. Genetic analysis with microsatellites from chromosome 18 confirmed the maternal origin of the extra chromosome 18. This is the first report of trisomy 18 in the baboon, which may be a promising animal model of human disease.     

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.     

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.     

Ultrasonic determination of fetal parameters in baboons (Papio anubis)

The use of nonhuman primates to study reproductive physiology, fetal development, and neonatal management often depends on the availability of pregnant and fetal animals of known gestational history. The purpose of this study was to establish and correlate normal fetal growth parameters with gestational age in olive baboons (Papio anubis). Normal cycling females were bred to proven males by using the degree of perineal swelling and vaginal cytology to determine onset of ovulation. The subjects were evaluated to determine pregnancy beginning 18 days postmating, using an Aloka-650 diagnostic ultrasound unit, equipped with a 7.5 mHz prostate probe and a 5 mHz transabdominal probe. Ten pregnant animals were then evaluated sonographically every 3 days through day 30 and weekly through day 135 (average gestation 184 days). Measurements included gestational sac, greatest-length, biparietal diameter, femur length, head circumference, and abdominal circumference. Using the means and standard deviations, growth curves were constructed, and the data used to develop predicted value charts for gestational age estimation. Using the predicted value charts established in our study, subsequent evaluation of pregnant baboons in our colony disclosed concordance with actual gestational age.     

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.     

Reduced reproductive function in wild baboons (Papio hamadryas anubis) related to natural consumption of the African black plum (Vitex doniana)

Several authors have suggested that the consumption of plant compounds may have direct effects on wild primate reproductive biology, but no studies have presented physiological evidence of such effects. Here, for two troops of olive baboons (Papio hamadryas anubis) at Gashaka-Gumti National Park, Nigeria, we show major seasonal increases in levels of fecal progesterone metabolites in females, and provide evidence that this is linked to the consumption of natural plant compounds. Increases in fecal progestogen excretion occurred seasonally in all females, in all reproductive states, including lactation. Detailed feeding data on the study animals showed that only one food species is consumed by both troops at the time of observed progestogen peaks, and at no other times of the year: the African black plum, Vitex doniana. Laboratory tests demonstrated the presence of high concentrations of progestogen-like compounds in V. doniana. Together with published findings linking the consumption of a related Vitex species (Vitex agnus castus) to increased progestogen levels in humans, our data suggest that natural consumption of V. doniana was a likely cause of the observed increases in progestogens. Levels of progestogen excretion in the study baboons during periods of V. doniana consumption are higher than those found during pregnancy, and prevent the expression of the sexual swelling, which is associated with ovulatory activity. As consortship and copulatory activity in baboons occur almost exclusively in the presence of a sexual swelling, V. doniana appears to act on cycling females as both a physiological contraceptive (simulating pregnancy in a similar way to some forms of the human contraceptive pill) and a social contraceptive (preventing sexual swelling, thus reducing association and copulation with males). The negative effects of V. doniana on reproduction may be counter-balanced by the wide-range of medicinal properties attributed to plants in this genus. This is the first time that physiological evidence has been presented of direct effects of plant consumption on the reproductive biology of wild primates.