The integration of an adult female gelada baboon (Theropithecus gelada)

An adult female gelada baboon has been integrated into an old-established group in the zoo in Rheine, West Germany. The integration took place in three steps: sight-contact, hourly meetings with the group, continuous stay in the group. Both the agonistic and the social-positive behaviour have been observed between the new female and the group-members. The integration was very difficult and lasted more than six months. The female was not really accepted, before she had not presented to the most dominant female of the one-male unit she has joined. This presenting only took place during the last part of the observations. In contrast to the adult female, the integration of juveniles occurred very quickly and nearly without any problems.     

Anti-predator behavior of gelada baboons

The anti-predator behavior of gelada baboons has been observed to consist of simple flight (i.e. they flee to cliffs after becoming alarmed by potential predators). However, active antipredator behavior was observed in a recently found gelada population in Arsi, Ethiopia. This population showed frequent active counter-attacks and severe mobbing at predators. Males fought domestic dogs on the plain and exhibited a systematic mobbing behavior towards a leopard on the cliff face to chase it off. These active anti-predator behaviors are the first confirmed reports on gelada baboons and may provide a useful insight for the understanding of the process of evolutionary adaptation to highland habitats by gelada baboons, as well as for the origin of this small southern population.     

A case of infanticide in a recently found gelada population in Arsi, Ethiopia

There have been no reports of infanticide in wild gelada baboons and it has been argued that infanticide is not necessary in geladas, since the birth interval of female gelada can be shortened after takeover of a unit by a new leader male without infanticide. However, we observed an instance of infanticide in a newly-found wild gelada population in the Arsi Region of Ethiopia. After a leader male of the unit was severely wounded by a leopard attack, he was quite weakened. The second male of the unit, a young adult male, became the leader of the unit three weeks later, but the former leader continued to stay in the unit as a second male. After a week, two other adult males joined the unit which, therefore, came to include four adult males. The infanticide took place nine days later. The perpetrator was one of the immigrant males and he showed great interest in the mother of the unweaned victim infant. Although the perpetrator copulated with her after the infanticide, the usurper was found to own all three adult females after two weeks following the infanticide; i.e. the perpetrator could not own any female. The wounded former leader showed conspicuous protective behavior towards the victim's mother and the dead infant. One possible explanation for the occurrence of infanticide in this population of geladas is as follows. Gelada males in this area may be able to join units more easily to form multi-male units but then have shorter tenure in the units. Facing the unstable condition of units, they may sometimes engage in infanticide to increase their breeding opportunities, even before becoming a leader.     

The distribution of baboon species and a new population of gelada baboons along the Wabi-Shebeli river,Ethiopia

We conducted an extensive survey in search of hybrid baboons betweenPapio hamadryas andP. anubis along the Wabi-Shebeli river at the border of the Arusi and Bale Regions, Ethiopia. We made inquiries of villagers on the roadsides concerning the existence of baboon species. We also conducted direct observations at several sites. There are three routes which lead to the north bank of the Wabi-Shebeli river (Arusi Region), and we found hybrid baboons on the bank of the Wabi-Shebeli river in two routes among the three. We found hamadryas baboons in all of the three routes at the cliff areas. There are two routes which lead to the south bank of the Wabi-Shebeli river (Bale Region). We conducted a survey on one of the two. We found hamadryas baboons at the cliff areas of the route. We observed a population of gelada baboons along the cliff extending over 20 km along the north bank of the Wabi-Shebeli river (Arusi Region). This area is far to the south of the known distribution range of gelada baboons (Yalden et al., 1977). The gelada baboons of this area appeared to represent a different form (subspecies?) from those at Debre Sina (Showa Region) based on our observations in both areas. We reached the conclusion that the distributions of baboon species along the Wabi-Shebeli river may have been strongly affected by the intensive cultivation on the plateau of the highland. The distribution patterns of the three baboon species,P. anubis, P. hamadryas, andTheropithecus gelada, appeared to be influenced by their individual adaptabilities to the cliff environment. Hamadryas baboons were distributed continuously along the cliff and the narrow lowland of the Wabi-Shebeli river. Anubis baboons were distributed discontinuously on the cliffs, and their populations tended to be small and isolated. These anubis baboons were strongly hybridized with hamadryas baboons.     

Vocalizations of adult gelada baboons (Theropithecus gelada): acoustic structure and behavioural context

Vocalizations and accompanying behaviors of adult gelada baboons were studied in four one-male groups kept in large outdoor enclosures in the zoos of Stuttgart and Rheine. Twenty-two acoustically different vocal patterns were determined. According to behavioural context, they were grouped into two categories: (1) contact calls and (2) aggressive and defensive calls. Frequency of calling and the production of different vocalizations were related to social rank and to the age of the sender. Vocalizations in species of the closely related genera Papio and Macaca are compared and their evolution is discussed.     

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.     

Infanticide in a chacma baboon troop

This report describes an infanticide and two attacks of an infant and a juvenile by a natal adult male in a troop of chacma baboons (Papio ursinus). The infanticidal male had become the dominant male in his troop five months before the infanticide suggesting that a trigger for infanticidal behavior is a rise in rank to dominant status.     

Saliva of the graminivorous Theropithecus gelada lacks proline‐rich proteins and tannin‐binding capacity

Gelada baboons are the sole survivors of the genus Theropithecus and the only known graminivorous primates. They developed special adaptations to their diet such as high‐crowned teeth for processing hard and abrasive feed. The fine‐tuning of salivary protein composition might be another key mechanism that is used by species for adapting to the environment and competing with rivals for exploiting new ecological niches. In order to test whether gelada (graminivorous) and hamadryas baboons (omnivorous) differ in their salivary protein composition, we compared whole saliva samples of captive Theropithecus gelada and Papio hamadryas using gel electrophoresis and tannin‐binding assay. We hypothesized that the amount of proline‐rich salivary proteins with tannin‐binding capacity is higher in baboons consuming a feed with high dicot/monocot rations. Dicots produce tannins as a chemical defense system, discouraging animals from eating them. In contrast to dicots, monocots do not synthesize tannins. The presence of tannin‐binding proteins in saliva should effectively inactivate the dicot tannin‐based defense mechanism and increase the dietary breadth and/or the capability to switch between monocots and dicot leaves. The lack of such tannin‐binding proteins in saliva would indicate a narrow dietary spectrum more restricted to monocots. We found T. gelada to completely lack proline‐rich proteins (PRPs) and tannin‐binding capacity similar to a great variety of other grazing mammals. In contrast, P. hamadryas does possess PRPs with tannin‐binding activity. The findings support a growing body of evidence suggesting a high‐level specialization of T. gelada to grass diets. However, it remains unclear, whether loss of salivary tannin‐binding capacity drove the gelada into its narrow feeding niche, or whether this loss is the result of a long process of increased specialization. Thus, from an ecological point of view, T. gelada appears to be more vulnerable to environmental changes than other baboon species owing to its narrow dietary traits. Am. J. Primatol. 71:663–669, 2009. © 2009 Wiley‐Liss, Inc.     

Defining Higher Levels in the Multilevel Societies of Geladas (Theropithecus gelada)

Multilevel societies, identified by two or more nested levels (or modules) of organization, have been touted as some of the most complex social systems. However, few empirical studies have effectively quantified the association patterns that delineate the various levels in such societies. In particular, the multiple levels of gelada society were first described >3 decades ago, yet no operational definitions exist for the higher levels, i.e., levels above the one-male unit. In geladas, multiple units form aggregations that fission and fuse throughout the day, and throughout the year, blurring the distinctions between previously described higher social levels: teams, bands, and communities. Here we use 5?yr of data on the daily composition of a population of geladas living in the Simien Mountains National Park, Ethiopia to test the hypothesis that higher levels of gelada organization are discrete entities. If gelada aggregations are nothing more than a group of units that share a home range, then we expect a continuous distribution of unit association. If, however, gelada aggregations are indeed discrete organizational levels, then we expect discontinuity in the patterns of association. We found significant discontinuity at the 50% association level, indicating a sharp distinction between members of the same band (>50% association) and members of the same community (<50% association). We also found evidence that recently fissioned units form teams that associate significantly more than other band members. Thus, despite their extremely fluid social organization, gelada social levels are nevertheless clearly identifiable and quantifiable. Based on these results, we suggest that gelada society is an extremely flexible, multilevel society with fission–fusion dynamics, and as such gelada society presents an unusual example for understanding the evolution of modular societies.     

Infanticide and juvenilicide in Hanuman langurs (Presbytis entellus) around Jodhpur,India

Ten cases of infant killings and 2 cases of juvenile killings were observed in two troops of Hanuman langurs, (Presbytis entellus) around Jodhpur, India. Fatal attacks on infants and juveniles are classified into four categories. The process of infanticide was observed from start to end and is described in detail for 3 cases. The age of the victims ranged from 0.2 to 48 months. The interbirth interval among females whose infants were killed is significantly shorter compared to females whose infants survived. In ourt study, 7 cases support the reproductive advantage hypothesis, that infanticide is an adaptive behaviour to increase male reproductive success. The remaining 5 cases do not fit into the reproductive advantage hypothesis. In these cases, victims are over 8 months old, and as such their deaths could not shorten the interbirth interval. It appears that by killing older infants and juveniles the males obtain an advantage in resource competition for their offspring. An alternative is that new males chase or peripheralise the older infants and juveniles, which leads to 97% predominant uni-male troop structure in Jodhpur.     

Intergeneric Hybrid Baboons

Though belonging to genera that have been distinct for several million years, gelada and common baboons—Theropithecus gelada and Papio hamadryas sensu lato, respectively—interbreed occasionally, even in the wild. A female hamadryas at Bihere Tsige Park, Addis Ababa, Ethiopia, apparently favored a gelada male over eligible conspecifics and produced several offspring with him. The F ₁ hybrids were large but developmentally normal. In skull and tooth form, and to a lesser extent in postcranial proportions, they were intermediate between the parental forms but lacked most of their parents' derived, (sub)species-specific epigamic characters. A female infant born to a subadult F ₁ was sired by a hamadryas. The backcross infant appeared normal and was still flourishing at about 2.5 years. Though perhaps impeded by natural selection against poorly adapted hybrids, theoretically interspecific hybridization could exceed mutation as a source of novel, preadapted genes in the wild.     

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.     

Comparing infant and juvenile behavior in bonobos (Pan paniscus) and chimpanzees (Pan troglodytes): a preliminary study

The dichotomy between the two Pan species, the bonobo (Pan paniscus) and chimpanzee (Pan troglodytes) has been strongly emphasized until very recently. Given that most studies were primarily based on adult individuals, we shifted the “continuity versus discontinuity” discussion to the infant and juvenile stage. Our aim was to test quantitatively, some conflicting statements made in literature considering species differences between immature bonobos and chimpanzees. On one hand it is suggested that infant bonobos show retardation in motor and social development when compared with chimpanzees. Additionally it is expected that the weaning process is more traumatic to chimpanzee than bonobo infants. But on the other hand the development of behaviors is expected to be very similar in both species. We observed eight mother–infant pairs of each species in several European zoos. Our preliminary research partially confirms that immature chimpanzees seem spatially more independent, spending more time at a larger distance from their mother than immature bonobos. However, the other data do not seem to support the hypothesis that bonobo infants show retardation of motor or social development. The development of solitary play, environmental exploration, social play, non-copulatory mounts and aggressive interactions do not differ between the species. Bonobo infants in general even groom other group members more than chimpanzee infants. We also found that older bonobo infants have more nipple contact than same aged chimpanzees and that the weaning process seems to end later for bonobos than for immature chimpanzee. Additionally, although immature bonobos show in general more signs of distress, our data suggest that the weaning period itself is more traumatic for chimpanzees.     

Adaptation to grass-eating in gelada baboons

Gelada faecal samples were analyzed for nutritional content and for particle size, and compared with similar data forPapio baboons, cattle, and zebra. Particle size in gelada is similar to that for zebra, larger than that for cattle and smaller than that for baboons. Gelada and baboons are less efficient than ungulates at extracting protein from their diet. The data on energy extraction are less easy to interpret and appear to be confounded by dietary and seasonal factors. It is suggested that gelada may be too large to compete effectively with ruminants in low altitude grassland habitats under the climatic conditions that have prevailed in eastern Africa since the late Pleistocene.     

Infanticide among free-ranging langurs (Presbytis entellus) at jodhpur (Rajasthan/India): Recent observations and a reconsideration of hypotheses

Considerable disagreement characterizes the debate concerning frequency, causation, and function of infanticide in connection with adult male replacements in bisexual one-male troops of hanuman langurs (Presbytis entellus). Detailed observations are presented about two noninfanticidal and three infanticidal male changes including six eye-witness and five presumed cases of infanticide within three langur troops during a long-term study at Jodhpur, Rajasthan, India. The results do not support any explanatory hypotheses focussing on social crowding, regulation of population density, social stress, sexual frustration, incest avoidance, or social bonding, but are in general though not total agreement with the reproductive advantage hypothesis: mainly unrelated infants were killed (one possible exception), the infanticidal male generally sired the subsequent offspring (one exception), and the mean interbirth interval subsequent to infanticide is by 2.1 months shortened. Likewise, several cases of stress induced abortions occurred. It is demonstrated that postconception estrous behaviour is by no means a female counterstrategy to infanticide in order to confuse males concerning the issue of paternity, since an infanticidal male did not spare the subsequent offspring of mothers who copulated with him during pregnancy and pregnant females did not discriminate between fathers and non-fathers.