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.     

Conflict management by hamadryas baboons (Papio hamadryas hamadryas) during crowding: a tension-reduction strategy

Primates change a variety of behavioral responses during short-term exposure to crowding. Under crowded conditions, rates of aggression, submissive behavior, and affiliative behavior may increase or decrease. Different patterns of change among these three categories of response have been interpreted as various coping "strategies" for managing the increased risk of conflict under crowded conditions. Grooming is of particular interest because this behavior is known to have a calming influence on the recipient and could be used to manage conflict under tense situations. A captive group of nine hamadryas baboons (Papio hamadryas hamadryas) composed of two harems was observed under short-term crowding to determine whether this species adopts conflict-management strategies similar to those described in other primates. The aggression, submission, affiliation, and displacement activities of the six adults in the group (two males and four females) were recorded, and behaviors in their small indoor quarters was compared with baseline behaviors in the outdoor section of their enclosure, which had over 10 times more space. Repeated-measures analysis of variance (ANOVA) was used to compare behavioral rates during crowding with baseline rates recorded immediately after crowding and during matched controls collected at the same time of day as the crowding sessions. Aggression and submission rates did not change significantly across conditions. Huddling together and proximity increased during crowding, and females increased grooming of their harem male during crowding. Displacement activities (e.g., pacing and self-grooming) increased during crowding, but scratching, an indicator of anxiety in primates, did not. The pattern of behavior exhibited by this group conforms to an active "tension-reduction" strategy in which animals successfully reduce the higher risk of aggression during crowding.     

Copulation patterns in captive hamadryas baboons: a quantitative analysis

For primates, as for many other vertebrates, copulation which results in ejaculation is a prerequisite for reproduction. The probability of ejaculation is affected by various physiological and social factors, for example reproductive state of male and female and operational sex-ratio. In this paper, we present quantitative and qualitative data on patterns of sexual behaviour in a captive group of hamadryas baboons (Papio hamadryas), a species with a polygynous–monandric mating system. We observed more than 700 copulations and analysed factors that can affect the probability of ejaculation. Multilevel logistic regression analysis and Akaike’s information criterion (AIC) model selection procedures revealed that the probability of successful copulation increased as the size of female sexual swellings increased, indicating increased probability of ovulation, and as the number of females per one-male unit (OMU) decreased. In contrast, occurrence of female copulation calls, sex of the copulation initiator, and previous male aggression toward females did not affect the probability of ejaculation. Synchrony of oestrus cycles also had no effect (most likely because the sample size was too small). We also observed 29 extra-group copulations by two non-adult males. Our results indicate that male hamadryas baboons copulated more successfully around the time of ovulation and that males in large OMUs with many females may be confronted by time or energy-allocation problems.     

A note on the effectiveness of behavioural rehabilitation for reducing inter-dog aggression in shelter dogs

The effectiveness of a rehabilitation program for reducing inter-dog aggression was evaluated at the municipal animal shelter. Sixteen dogs (of 60 examined) met the study criteria of medium inter-dog aggression as determined by an inter-dog aggression test. These dogs received a 10-day treatment of daily rehabilitation for 30 min (rehabilitation group, n = 9) or daily release into an outdoor enclosure for 30 min (control group, n = 7). Rehabilitation consisted of desensitising and counter-conditioning dogs to the approach of other “stimulus” dogs. Most dogs in the rehabilitation group showed a decline in aggression scores when re-tested after the last treatment (day 11), and differed significantly from the control dogs which showed either an increase or no change in aggression scores (U = 8.5, P < 0.01). Rehabilitation dogs also showed lower frequencies of aggressive body postures (“facing the stimulus dog”, P < 0.05, and “stiff posture”, P < 0.10) and higher frequencies of less assertive postures (“ears back”, P < 0.05, and “lowered neck”, P < 0.10) on day 11. The differences between groups were no longer significant when a reduced sample of dogs was tested 1 week after rehabilitation ended (day 18). The study shows short-term reduction of inter-dog aggression through rehabilitation, but further work is needed on effective ways of maintaining the behavioural change.     

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.     

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.     

The Socioecology of Network Scaling Ratios in the Multilevel Society of Hamadryas Baboons (Papio hamadryas hamadryas)

Multilevel or modular societies characterize a range of mammalian taxa, allowing social groups to fission and fuse in response to ecological factors. The modular society of hamadryas baboons has previously been shown to consist of 4 levels: troop, band, clan, and one-male unit (OMU). A recent study by Hill et al. (Biology Letters 4:748–751, 2008) revealed a mean scaling ratio across successive levels of multilevel societies of ca. 3; this was consistent across elephants, orca, geladas, and hamadryas baboons. Here we reanalyze the scaling ratio for hamadryas baboons with previously unavailable data from Filoha. Our analysis revealed a mean scaling ratio for hamadryas of 3.28 without data on the hamadryas clan layer of organization at Filoha, but a ratio of 6.17 with these data included. This discrepancy is due to the large clan and band sizes at Filoha yielding a larger than average gap between the OMU and the clan. Further analysis revealed subsets of OMUs within clans, suggesting a 5th level of society in this population. When this 5th layer of social structure is included in the analysis, the scaling ratio at Filoha is consistent with that of other hamadryas populations and other taxa. These results suggest that a consistent mammalian scaling ratio can be used to detect previously hidden levels of organization within societies and to predict their sizes in taxa for which detailed behavioral data are not available.     

Function of Notification in Papio hamadryas

Notification is a form of ritualized greeting behavior performed by adult male hamadryas baboons (Papio hamadryas). Originally observed in the wild when harem leaders signaled the direction of travel to their followers on daily foraging marches, its true function is unknown. Notification involves the approach of an adult male baboon to another male, the presentation of his hindquarters, then retreat. Researchers have previously linked notification to aggression avoidance, appeasement, and the dominance-subordination relationship between males. We observed instances of notification over 6 mo among 8 adult males in a troop of 61 captive-bred hamadryas baboons at Paignton Zoo Environmental Park, Devon, UK. We compared observation sessions in which notification occurred with matched control periods. We classified different forms of notification according to the recipient’s response: presenting, mounting, touching of the buttocks or genitals, or ignoring. Results suggest that different forms of notification may have different functions, including submission, alliance, and peacekeeping but not general greeting, recruitment, or appeasement.     

Body Temperature and Physical Activity Correlates of the Menstrual Cycle in Chacma Baboons (Papio hamadryas ursinus)

We investigated the temporal relationship between abdominal temperature, physical activity, perineal swelling, and urinary progesterone and estradiol concentrations over the menstrual cycle in unrestrained captive baboons. Using a miniature temperature‐sensitive data logger surgically implanted in the abdominal cavity and an activity data logger implanted subcutaneously on the trunk, we measured, continuously over 6 months at 10‐min intervals, abdominal temperature and physical activity patterns in four female adult baboons Papio hamadryas ursinus (12.9–19.9 kg), in cages in an indoor animal facility (22–25°C). We monitored menstrual bleeding and perineal swelling changes, and measured urinary progesterone and estradiol concentrations, daily for up to 6 months, to ascertain the stage and length of the menstrual cycle. The menstrual cycle was 36 ± 2 days (mean ± SD) long and the baboons exhibited cyclic changes in perineal swellings, abdominal temperature, physical activity, urinary progesterone, and estradiol concentrations over the cycle. Mean 24‐hr abdominal temperature during the luteal phase was significantly higher than during the periovulatory phase (ANOVA, F_{(2, 9)} = 4.7; P = 0.04), but not different to that during the proliferative phase. Physical activity followed a similar pattern, with mean 24‐hr physical activity almost twice as high in the luteal than in the periovulatory phase (ANOVA, P = 0.58; F_{(2, 12)} = 5.8). We have characterized correlates of the menstrual cycle in baboons and shown, for the first time, a rhythm of physical activity and abdominal temperature over the menstrual cycle, with a nadir of temperature and activity at ovulation. Am. J. Primatol. 74:1143‐1153, 2012. © 2012 Wiley Periodicals, Inc.     

Human–hamadryas baboon (Papio hamadryas) conflict in the Wonchit Valley,South Wollo,Ethiopia

Understanding the extent of human–primate conflict is crucial to the development of conservation and management strategies. We carried out this study in an unprotected area of central Ethiopia to examine the magnitude of human–hamadryas baboon (Papio hamadryas) conflict and to assess the attitude of local farmers towards baboons in Wonchit Valley. In 2014, we interviewed 119 adult respondents using a structured questionnaire. Local farmers considered hamadryas baboons to be the major pest in the area. All respondents reported that hamadryas baboons caused crop raiding and small livestock predation in the region. Respondents reported that a shortage of fruit producing wild trees and ready availability of crops were the main causes of conflict between farmers and hamadryas baboons. We found that hamadryas baboons damaged cereal crops at dusk and dawn during full moonlight, and most (89.9%) respondents claimed that they were not interested in hamadryas baboon conservation. Our results indicate that human–hamadryas baboon conflict has a strongly negative impact on both baboon conservation and local farmers. We suggest that to mitigate the human–hamadryas baboon conflict, job opportunities such as beekeeping should be introduced in the region.     

Teeth emergence in wild olive baboons in Kenya and formulation of a dental schedule for aging wild baboon populations

Teeth emergence schedules are presented from analysis of 95 wild olive baboons Papio anubis (age range 2–120 months) and compared to recently published results for wild and captive yellow baboons (P. cynocephalus; Phillips-Conroy and Jolly: American Journal of Primatology 15:17–29, 1988). Age at emergence of M1 (20.5 months males, 19.5 months females), I1 (32.5 and 33.5 months) and I2 (40.0 and 39 months) of olive baboons was earlier than in the wild yellow baboons and similar to captive yellow baboons. However, the later emerging teeth were delayed considerably relative to the captive animals and were similar in age of emergence to those of wild yellow baboons. Considerable variation in age of emergence occurred in the later emerging teeth especially among males. Regression analysis of dental scores with age demonstrated differences between olive baboons and captive yellow baboons but not between olive baboons and wild yellow baboons. Combined data on dental scores for wild yellow, olive, and hamadryas baboons provide schedules of AGE (months) = {SCORE – 11.79} ÷ 0.4405 and AGE (months) = {SCORE – 11.24} ÷ 0.4797 for males and females, respectively, which may be used for aging wild baboons. Full permanent dentition in wild baboons is predicted to occur over 1 year later than in captive animals.     

Space use as an indicator of enclosure appropriateness: A novel measure of captive animal welfare

Empirical measures of animal behavior and space use within the captive environment can provide critical information about animals’ requirements, preferences and internal states. The trend toward naturalistic environments has shown promise in terms of behavioral benefits for animals such as great apes, and there have been several studies of the effects of complex environments on captive apes. However, few recent investigations have objectively compared environmental preferences between two distinct enclosures. In this study, we assessed how ape space use varied within and across two very different environments: an indoor, hardscape enclosure and an indoor/outdoor, naturalistic enclosure. Within-facility tests were conducted by comparing data from behavioral observations of the apes’ position in the enclosures to measurements of the space and the availability of individual environmental elements. Between-facility comparisons utilized electivity index calculations to assess both the degree of use for specific features and the degree to which these selections strengthened or weakened in the new facility. Both gorillas and chimpanzees showed significant structural preferences in the older, hardscape environment: positioning themselves by mesh barriers (chimpanzees: P = 0.005; gorillas: P < 0.001) and corners (P = 0.005; gorillas: P < 0.001) more than would be expected by random spatial utilization, and avoiding open spaces (chimpanzees: P = 0.005; gorillas: P < 0.001) not adjacent to any physical structure. A new, naturalistic enclosure was constructed using preference data from the previous facility. In the new facility, both species of ape substantially altered the way in which they chose to position themselves in the enclosure. Chimpanzees used most of the environmental elements at rates more similar to the proportions they were available. While gorilla's preference corners was maintained in the new facility, preferences for doorways and mesh barriers disappeared. Comparing electivity indices facilitated an empirical comparison of space use preferences. Chimpanzees showed significant differences in how they used structural elements (P = 0.021), mesh barriers (P = 0.009) and corners (P = 0.016) in the new facility. Gorillas’ environmental selections were similarly altered in the new facility, as selections of areas adjacent to doorways (P = 0.003), glass barriers (P = 0.005), structural elements (P < 0.001), and mesh barriers (P = 0.012) were all significantly affected by the transfer. This approach is useful for understanding how captive animals utilize their enclosures and we advocate that electivity indices can be added to a growing list of tools to assess the effect of captive environments on animal welfare.     

Greeting movements among adult males in a colony of baboons:Papio hamadryas,P. cynocephalus and their hybrids

Seven greeting movements performed by four adult males belonging to a colony of baboons (Papio hamadryas, P. cynocephalus and their hybrids) were described. The hamadryas male has more number and more refined repertoire of movements than the yellow baboons, what would mean that the greeting movements possess a species-specific nature. This characteristic is expressed also by the existence of some inappropriate responses of the yellow baboons to the greeting of the hamadryas male. The differences in the greeting movements between both species would be explained as characteristic consequences of their social system organization. The hybrid male, having acquired a system organization similar to that of the hamadryas male, has acquired the same signal code, too, according to this system. The hybridization tendency would be adaptive in those colonies or troops with mixed species.     

DNA fingerprinting and the problems of paternity determination in an inbred captive population of guinea baboons (Papio hamadryas papio)

Multilocus DNA fingerprinting was carried out on 65 individuals from a captive colony of guinea baboons (Papio hamadryas papio) at Brookfield Zoo, in order to determine the allocation of reproductive success among 7 active males. DNA fingerprinting was found to reveal very low levels of genetic variability in the study population, rendering discrimination of different levels of relatedness, and hence paternity, impossible. A method was therefore developed for emphasizing the region of the fingerprint pattern which revealed the greatest level of band variability, and the effect of this experimental modification on band sharing statistics was tested. Band sharing coefficients among unrelated individuals were significantly lower using the modified system, which was then applied to paternity testing in the whole population. However even when using the modified system, of the 33 offspring analyzed only 4 could be assigned solely to 1 male, 14 offspring were assigned to 1 of 2 males, 7 offspring had 3 potential fathers, and the remainder had 4 or more possible fathers. The implications of the limitations of these data for behavioural studies and genetic management of captive populations are discussed.     

Crossing the Red Sea: phylogeography of the hamadryas baboon, Papio hamadryas hamadryas

The hamadryas baboon (Papio hamadryas hamadryas) is found both in East Africa and western Arabia and is the only free-ranging nonhuman primate in Arabia. It has been hypothesized that hamadryas baboons colonized Arabia in the recent past and were possibly even transported there by humans. We investigated the phylogeography of hamadryas baboons by sequencing a portion of the control region of mtDNA in 107 baboons from four Saudi Arabian populations and combing these data with published data from Eritrean (African) P. h. hamadryas. Analysis grouped sequences into three distinct clades, with clade 1 found only in Arabia, clade 3 found only in Africa, but clade 2 found in both Arabian and African P. h. hamadryas and also in the olive baboon, P. h. anubis. Patterns of variation within Arabia are neither compatible with the recent colonization of Arabia, implying that baboons were not transported there by humans, nor with a northerly route of colonization of Arabia. We propose that hamadryas baboons reached Arabia via land bridges that have formed periodically during glacial maxima at the straits of Bab el Mandab in the southern Red Sea. We suggest that the genetic differentiation of Arabian from African populations suggests that Arabian populations have a higher conservation status than recognized previously.     

Prevalence and geographical distribution of Papio hamadryas papillomavirus 1 (PhPV1) in Kenyan baboons

Papio hamadryas papillomavirus (PhPV) 1, 2, and 3, are Alphapapillomaviruses that have been detected in Kenyan Olive baboons but the distribution is unknown. Therefore, cervical screening for PhPV1 was performed in baboons from various areas in Kenya using a nested polymerase chain reaction. The prevalence rate was 33%.     

Rank and grooming reciprocity among females in a mixed-sex group of captive hamadryas baboons

In a mixed-sex, captive group of hamadryas baboons (Papio hamadryas hamadryas) we investigated whether female grooming relationships are affected by their dominance ranks. Seyfarth's [1977] grooming for support model and Barrett et al.'s [1999] biological market model both predict that in primate groups where competition for monopolizable resources is high, grooming among females is based, at least partly, on the interchange of grooming for rank-related benefits, and that rank thus influences the distribution of grooming in females. Contrary to this prediction, our results show that despite the existence of a linear dominance hierarchy, rather strict dominance relationships, and high food-related aggression rates, grooming among female hamadryas baboons is not affected by rank and is only exchanged for itself. This is understandable since rank differences in our study group only result in differential access to limited, preferred food items that are not actively shared. Although some females are more likely to tolerate one another at the food pile, this tolerance is not determined by their grooming efforts and interchange of grooming for rank-related benefits does not occur. We conclude that female hamadryas baboons groom others in order to be groomed by them, which is supported by our observation that grooming reciprocity within a dyad increases when more grooming occurs in this dyad. Our results indicate that grooming is indeed a valuable commodity in itself, probably because of its stress- and tension-reducing effect. Based on our findings, the existing groom trade model is extended to include circumstances in which monopolizable resources are available but are not traded for grooming.     

Migration of male hamadryas baboons into anubis groups in the Awash National Park,Ethiopia

Among “savanna” baboons, males are the dispersing sex, and females are philopatric. Despite clear evidence for migration of adult males at Erer-Gota, Ethiopia (Abegglen, 1984), it is generally believed that a different pattern-dispersal only by female transfer-is found in hamadryas baboons,Papio hamadryas hamadryas (Pusey and Packer, 1987; Pusey, 1988; Stammbach, 1987). Since the late 1960's, there have been isolated observations of hamadryas males migrating into anubis groups in the Awash National Park, Ethiopia (Nagel, 1973; Kawai and Sugawara, 1976; Sugawara, 1982). Since 1983, we have observed 11 individually identified adult hamadryas immigrants in four anubis groups above the Awash Falls and have trapped and tagged 9 of them. One subadult male was also captured and marked. Repeated visits to the study site allow us to document long-term residence of these “cross-migrant” males in their host groups. The longest-resident male has been in the same group for 5 years or more; a conservative estimate of the average length of residence is 3 years. We estimate that 25 hamadryas males have moved into this ozne over the last 15 years. Although larger than the hamadryas males captured in 1973, all but one of our cross-migrants appear phenotypically hamadryas. By comparing, the ages of our cross-migrants with Abegglen's account of the typical hamadryas male life-history, we have found that the adult hamadryas males seem to immigrate at ages consistent with having left their     

Indication of higher salivary α‐amylase expression in hamadryas baboons and geladas compared to chimpanzees and humans

Background Little is known about salivary α‐amylase expression in primates. Methods We compared saliva of gelada and hamadryas baboons, chimpanzees and humans using SDS‐PAGE and immunoblotting. Results and conclusions Amylase expression was increased in hamadryas baboons (P = 0.0376) compared to humans and might indicate dietary starch use in Cercopithecines.     

Skewed birth sex ratio and premature mortality in elephants

Sex allocation theories predict equal offspring number of both sexes unless differential investment is required or some competition exists. Left undisturbed, elephants reproduce well and in approximately even numbers in the wild. We report an excess of males are born and substantial juvenile mortality occurs, perinatally, in captivity. Studbook data on captive births (CB, n = 487) and premature deaths (PD, <5 years of age; n = 164) in Asian and African elephants in Europe and North America were compared with data on Myanmar timber (Asian) elephants (CB, n = 3070; PD, n = 738). Growth in CB was found in three of the captive populations. A significant excess of male births occurred in European Asian elephants (ratio: 0.61, P = 0.044) and in births following artificial insemination (0.83, P = 0.003), and a numerical inclination in North American African elephants (0.6). While juvenile mortality in European African and Myanmar populations was 21–23%, it was almost double (40–45%) in all other captive populations. In zoo populations, 68–91% of PD were within 1 month of birth with stillbirth and infanticide being major causes. In Myanmar, 62% of juvenile deaths were at >6 months with maternal insufficient milk production, natural hazards and accidents being the main causes. European Asian and Myanmar elephants PD was biased towards males (0.71, P = 0.024 and 0.56, P < 0.001, respectively). The skewed birth sex ratio and high juvenile mortality hinder efforts to help captive populations become self-sustaining. Efforts should be invested to identify the mechanism behind these trends and seek solutions for them.