Gelada Research Articles

Marginalized Groups of Gelada (Theropithecus gelada) Living in and around the Highly Disturbed Mount Guna Community Conservation Area, Northwest Ethiopia

Gelada (Theropithecus gelada) is the only surviving primate of the genus Theropithecus that is endemic to Ethiopia. It adapted to live in afroalpine and subafroalpine ecosystems of the Ethiopian alpine. Although it is at risk of habitat loss due to agricultural expansion and deforestation, gelada has been classified as a least concern by the IUCN. Gelada has great importance as it represents the Ethiopian national treasure which brings tourists to the country. However, no proper gelada census has been carried out in and around Mount Guna (Mt. Guna). Therefore, the current study aimed to provide an accurate count of gelada individuals living in the study area. Total count along line transects was carried out from January 1–May 30, 2018, to estimate the population of gelada. According to the current result, gelada individuals counted from the entire sites of Mt. Guna were estimated to be 56. Forty-two gelada individuals were counted from outside the protected area, while 14 of them were from the protected area. There was a significant difference between gelada individuals counted from inside and outside the protected areas (P = 0.047). The ratio of age-sex of geladas also computed to be adult males: adult females: subadult males: subadult females: immature is 1 : 3.12 : 0.88 : 1.25 : 0.75 for the total population. Furthermore, five groups of geladas were observed outside the Mt. Guna community conservation area at three sites, while only one group of geladas was identified from the protected area. Based on the current result, we recommend further research to study the population trend, fertility problems, and conservation mechanisms of geladas living within the agricultural land and human-gelada conflicts around Mt. Guna.

‘I am not an animal’: Vikram Balagopal’s psychologisation of Hanuman in Simian

ABSTRACT This article discusses Vikram Balagopal’s mythological Indian graphic narrative Simian (2014), which is a retelling of particular episodes from the Ramayana from Hanuman’s point of view. The essay claims that Balagopal’s portrayal of Hanuman as a gelada baboon strips him of devotional/religious signifiers and allows readers to see him as a secular figure. The graphic narrative portrays this popular Hindu god as a heavily psychologised figure grappling with the ramifications of his special abilities, and questioning his liminal identity in the face of derogatory classifications by human beings. This representation is in opposition to the co-optation of Hanuman as a hyper-masculine warrior by an aggressive, resurgent Hindu nationalist movement. Simian also uses a reflective Hanuman to critique Ramayana’s anthropocentricism and gender and caste biases. It thus places itself into a long tradition of interrogative and subversive retellings of the Ramayana.

Bridging Captive and Wild Studies: Behavioral Plasticity and Social Complexity in Theropithecus gelada.

Simple SummaryAnimals are able to flexibly adjust their behavior according to both physical and social environmental changes. In this view, multiple data collections carried out in different settings are crucial to understand proximate and ultimate causes of such a behavioral plasticity. By selecting Theropithecus gelada as a model, we suggest that the complementary strengths and weaknesses of research in captive and wild settings makes such a hybrid approach particularly relevant. By providing information at different scales, the two settings can give a fuller picture of a behavioral trait. The apparent incongruity in behavior across captive and wild data is itself a powerful tool to explore behavioral plasticity and latent propensities. Finally, the two settings allow validating and exploring behavioral aspects that are noticed in the other settings. We really hope that our experiences and ideas can be helpful in stimulating other researchers to consider the captive-wild approach as a valid opportunity to reach a fuller picture of the behavior they are studying.Cognitive ethology explores the ability of animals to flexibly adapt their behavior to rapid physical and social environment fluctuations. Although there is a historical dichotomy between field and captive studies, recently, a growing interest in questions that sit at the intersection of cognitive and adaptive perspectives has helped bridge this divide. By focusing on Theropithecus gelada, we discuss the three main reasons why this hybrid approach is extremely successful. First, captive and wild studies provide data at different social, spatial, and temporal scales that can be synthesized to give a fuller picture of the behavior. Secondly, apparently conflicting results from captive and wild settings are powerful tools to explore behavioral flexibility and latent behavioral tendencies. Third, the different settings provide ways of validating and exploring behaviors that are noticed in the other setting. Although we were able to bring together our captive and wild research to demonstrate these ideas, we could have obtained a more integrated vision on the proximate and ultimate gelada behavioral and cognitive strategies if we had considered this hybrid approach from the beginning. We hope that this manuscript stimulates scholars in designing their studies by taking into account the incredible potential of a complementary captive-wild research approach.

Human-olive baboon (Papio anubis) conflict in the human-modified landscape, Wollo, Ethiopia

Human–wildlife conflicts are increasing worldwide, and are typically most intense in human-dominated unprotected areas where local people, livestock and wildlife share the same landscapes. Such conflict becoming severe as wildlife species damage crops and predate livestock, and the subsequent factors undermine wildlife conservation efforts in a region. Between March and June 2017, I conducted a questionnaire-based interview with 124 local farmers to examine the extent of human-olive baboon (Papio anubis) conflict and their conservation attitudes towards baboons in Wollo, Ethiopia. All respondents reported that crop foraging and small livestock (sheep and goats) predation were the two main human-olive baboon conflict causes in the region. Most respondents placed olive baboons as the second most destructive crop pest after geladas (Theropithecus gelada), and as the first most small livestock predator followed by leopard (Panthera pardus). Most farmers placed bean (Vicia faba) as the first most frequently raided crop by olive baboons followed by sorghum (Sorghum bicolor) and maize (Zea mays). In the two years period (between 2015 and 2016), most (70.2%) respondents claimed that they lost their small livestock to olive baboons, with an annual average loss of 2.5 heads per year, equivalent to US$ 52.26. I found that most (80.7%) respondents had negative attitudes towards olive baboons, and 81.9% were not interested to olive baboon conservation in their localities. Most farmers agreed guarding as the best mitigation measures to minimize crop and livestock losses. The result shows that human-olive baboon conflicts create negative impact on both farmers’ livelihood and baboon conservation in the region. I suggest that to mitigate human-olive baboon conflict shifting guarding system among local farmers as the means of keeping crop fields and small stock, and educating people about the ecosystem services of baboons as well as creation of a protected area should be considered in the region.

First evidence of yawn contagion in a wild monkey species

Yawn contagion occurs when individuals yawn in response to the yawn of others (triggers). This is the first account of yawn contagion in wild geladas (Theropithecus gelada), a monkey species that shows yawn contagion in captivity and is organized in core units (one-male/bachelor groups) forming multilevel associations. In a population of geladas from the Kundi plateau (Ethiopia) we found that the yawning response was highest when geladas could perceive a triggering yawn, which confirms that yawn contagion is present in the wild. Yawn duration, mouth-opening degree and presence/absence of vocalisation (possibly modulating yawn detectability) did not affect the likelihood of contagion. Males and females, known to be both implicated in movement initiation within groups, were similarly powerful as yawn triggers. Instead, group membership and responder sex had a significant role in shaping the phenomenon. Yawn contagion was highest between individuals belonging to different core units and males were most likely to respond to others’ yawns. Because males have a non-negligible role in inter-group coordination, our results suggest that yawn contagion may have a communicative function that goes beyond the basic unit level.

In silico comparative analysis of BRCA2 gene in some selected animal species in Africa

Background: BRCA2 genes are not only found in humans, but in other animal species. BRCA2 gene plays a vital role in maintaining the stability of a cell's genetic information. BRCA2 is considered as a gatekeeper gene; however, if mutated or abnormally expressed, it causes the destruction of normal cell structure and promotes the growth of cancer cells. Objective: This study aimed to assess the differences and similarities of BRCA2 gene from different animal species in Africa through In silico genomics analysis providing further insight on its comparative genomics features. Materials and Methods: Fifteen nucleotide sequences of BRCA2 gene of different mammals and bird species were retrieved from National Centre for Biotechnology Information (NCBI). Multiple sequence alignment was done with MEGA 7.0 software, while identity and similarities were determined by constructing a pairwise comparison. Conserved domains on the sequences were identified with NCB1-CDD. Results: BRCA2 gene was found to be present not only in humans, but other lower animals and birds across African countries. The phylogenetic tree for Homo sapiens BRCA2 gene in Tunisia belongs to the same ecological niche with the Theropithecus gelada BRCA2 gene in Ethiopia and BRCA2 from the same African region has high bootstrap, implying that they share the same homology. Conserved regions identified in the all the sequences were absent in Miniopterus natalensis and most present in Chrysochloris asiatica, Theropithecus gelada, Apaloderma vittatum, Pterocles gutturalis, Rousettus aegyptiacus, Homo sapiens, Echinops telfairi, and Cavia porcellus. Conclusion: Based on the findings obtained from this study, BRCA2 gene in humans and other lower animals, particularly from same region, share the same homology and similarities.

Feeding ecology and diet of the southern geladas (Theropithecus gelada obscurus) in human-modified landscape, Wollo, Ethiopia.

Studying the dietary flexibility of primates that live in human‐modified environments is crucial for understanding their ecological adaptations as well as developing management and conservation plans. Southern gelada (Theropithecus gelada obscurus) is an endemic little‐known subspecies of gelada that inhabits human‐modified landscapes in the northern central highlands of Ethiopia. During an 18‐month period, we conducted this intensive study in an unprotected area of a human‐modified landscape at Kosheme in Wollo to investigate the feeding ecology of southern geladas and their dietary responses to seasonal variations. We quantified the monthly and seasonal diet data from a band of southern geladas using instantaneous scan sampling method at 15‐min intervals, and green grass phenology and availability using visual inspection from the randomly selected permanent plots. The overall average diet of southern geladas at Kosheme constituted grass blades 55.4%, grass undergrounds 13.2%, grass bulbs 5.6%, grass seeds 5.4%, herb leaves 4.0, fruits 7.3%, and cereal crops 5.6%. Grass blade consumption increased with increasing green grass availability, while underground food consumption increased with decreasing green grass availability, and vice versa. Southern geladas spent significantly more time feeding on the grass blades and herb leaves and significantly less time on bulbs during the wet season than the dry season. Underground grass items (rhizomes and corms) were not consumed during the wet season, but made up 22.3% of the dry season diet. Thus, although grass blades are staple diet items for geladas, underground diet items are important “fallback foods” at Kosheme. Our result shows insights into the dietary flexibility southern geladas adopt to cope with human‐modified landscapes of the north‐central Ethiopian Highlands. Thus, the study contributes to a better understanding of how changing environments shape primate ecology and evolution.

Activity time budgets of ecologically relaxed groups of geladas (Theropithecus gelada) and mandrills (Mandrillus sphinx): what happens when time is no longer a constraint?

Primates spend their daytime engaged in four non-overlapping, time-consuming, biologically relevant activities, namely, feeding, moving, resting, and socializing. The present study addressed two issues relevant to socio-ecological theory and life-history theory: how do individuals re-schedule the time allocated to these activity categories when they live in ecologically relaxed settings, where they are food-provisioned, live under benign weather conditions, and are predator-free? How do individuals trade the different activity categories against each other in a relatively time constraint-free setting? We predicted that feeding and moving times should decrease and resting and socializing times should increase. We also explored the relation of feeding time to resting time and social time to see which activity category is more dispensable when feeding time increases. Here we analyzed the activity time budgets of a group of geladas, Theropithecus gelada, and a group of mandrills, Mandrillus sphinx, housed in captivity in similarly vegetated and large-sized enclosures, and exposed to identical temperate-zone climate conditions, and compared them to time budget data available for wild groups of geladas and baboons. We found that they displayed activity budgets that largely matched those reported for wild groups of geladas and baboons, except moving time that decreased, but in geladas solely. We also found a tighter negative relation of feeding to resting time than to social time. These findings indicate that freeing individuals in a captive setting from the time constraints and pressing demands faced by their wild counterparts does not necessarily cause a significant re-scheduling of their activity time budgets. They also support the “social glue” hypothesis, as an increase of feeding time is associated with a significant decrease in resting, not social, time. The notion of a captivity-typical versus wild-typical profile of activity time budgets appears unsupported given the remarkable overlapping of time budget scores across settings and the huge inter-populational, intergroup, and intragroup variation reported.

Extragroup paternity in gelada monkeys, Theropithecus gelada, at Guassa, Ethiopia and a comparison with other primates

Following the introduction of DNA fingerprinting in the 1980s, studies have repeatedly revealed mismatches between the mating system inferred from social behaviour and the mating system revealed through genetic relationships. In this study, we examined the occurrence of extragroup paternities (EGPs) in gelada monkeys at Guassa, Ethiopia and explored how EGPs may be acquired in this species, which is conventionally considered to have a single breeding male (‘leader’) per social group (‘unit’). We found that while leaders sired most offspring, a substantial proportion (17 of 88 offspring, 19%) were sired by extra-unit males. Offspring were more likely to be sired by extra-unit males when they were: (1) conceived in the 6 months following the start of peak rainfall (July–December) and (2) the first successful conception for a mother. Furthermore, eight of the 17 extra-unit paternities were directly or indirectly the result of a single infertile leader, indicating that infertility plays an important role in the occurrence of EGPs. Compiling published data revealed that the 19% EGP rate observed among Guassa geladas was also the median for polygynous nonhuman primates (range 0–57%, N = 5 populations), in contrast to geladas in the Simien Mountains, where EGPs are absent or rare. Thus, intraspecific variation in EGP rates in geladas encompasses much of the range described across polygynous primates more broadly. The Guassa gelada EGP rate was similar to the median rate reported for mammals. Primates generally had a lower median rate of EGPs, more similar to the median rate reported for birds. Understanding variation in EGP rates requires understanding the outcomes of competing interests of males and females within the same species, as well as how these features contribute to the evolution of social systems and influence variation in EGP rates at higher taxonomic levels. • Geladas at Guassa have higher extra-unit paternity rates than reported elsewhere. • Seasonal variation, parity and infertility influence extragroup paternity (EGP). • Polygynous primates have the highest median EGP rate. • Multimale groups better prevent EGPs but risk sharing paternity with group members. • Humans generally have low EGP rates compared to other primates.

Looking into each other's eyes makes it better: eye-to-eye contact enhances sexual interactions in wild geladas

In human and nonhuman primates eye-to-eye contact (EEC), a face-to-face communication component, can promote emotional/attentional engagement and prolong affiliative interactions. Owing to its direct impact on fitness, the reproductive context is perhaps the most critical context for investigating EEC's importance. However, the presence of this phenomenon around mating and its functions in primates is still understudied. In this work, we investigated whether EEC was present during copulations and influenced the copula duration and postcopulation grooming occurrence in the wild gelada, Theropithecus gelada , an Old World monkey species. We found that the previous presence of the male ‘look-at’ triggered the female ‘look-at’. Moreover, copulations were most likely to last longer in the presence of EEC. In addition, the occurrence of postcopulation grooming between partners, most frequently initiated by females, increased when copulations included EEC. Females' engagement in EEC with the male may be a form of continuation of female precopulatory proceptivity and facilitate males' copulatory activity. By prolonging sexual contacts, EEC may also increase the chances of ejaculation. By grooming their partners after mating, female geladas may attempt to reduce male arousal and prolong the social interaction with them, possibly strengthening their social bond. These results provide the first quantitative evidence that EEC is an effective mechanism for prolonging mating interactions and enhancing postmating affiliation in a Papionini species. On a broader perspective, the presence of EEC in an Old World monkey species suggests that EEC may have been favoured by natural selection to promote reproductive advantages during human evolution. • Eye-to-eye contact is little studied in the mating context. • Gelada females can look at and establish eye contact with males during copulation. • Eye-to-eye contact increases copula duration and possibly reproduction success. • Eye-to-eye contact increases postmating grooming and possibly male-female cohesion. • Eye-to-eye contact strengthens social bonds between mates in monkeys.

The Goldilocks effect: female geladas in mid-sized groups have higher fitness.

The cost–benefit ratio of group living is thought to vary with group size: individuals in ‘optimally sized’ groups should have higher fitness than individuals in groups that are either too large or too small. However, the relationship between group size and individual fitness has been difficult to establish for long-lived species where the number of groups studied is typically quite low. Here, we present evidence for optimal group size that maximizes female fitness in a population of geladas (Theropithecus gelada). Drawing on 14 years of demographic data, we found that females in small groups experienced the highest death rates, while females in mid-sized groups exhibited the highest reproductive performance. This group size effect on female reproductive performance was largely explained by variation in infant mortality (and, in particular, by infanticide from immigrant males) but not by variation in reproductive rates. Taken together, females in mid-sized groups are projected to attain optimal fitness due to conspecific infanticide and, potentially, predation. Our findings provide insight into how and why group size shapes fitness in long-lived species.

Wild geladas (Theropithecus gelada) in crops\u2014more than in pasture areas\u2014reduce aggression and affiliation

Human–primate interfaces are expanding and, despite recent studies on primates from peri-urban environments, little research exists on the impact of agriculture and/or pasture areas on primate social behavior and health. We assessed how crop/pasture areas potentially alter social behavior and health of wild geladas (Theropithecus gelada) frequenting the unprotected area of Kundi (Ethiopia). We predicted that compared to pasture areas, crop areas (i) would be more challenging for geladas (prediction 1) and (ii) would have a greater impact on both aggressive and affiliative behavior, by reducing grooming time and enhancing competition (prediction 2). During January–May 2019 and December 2019–February 2020, we collected data (via scan, focal animal sampling, and video analyses) on direct human disturbance, external signs of pathologies and social behavior of 140 individuals from 14 one-male units and two all-male units. Animals experienced the highest level of human disturbance in crop areas (in line with prediction 1). Individuals from the groups preferentially frequenting crop areas showed the highest prevalence of external signs of pathologies consistent with chemical and biological contamination (alopecia/abnormally swollen parts). We collected 48 fecal samples. Samples from frequent crop users contained the highest rates of parasitic elements/gram (egg/larva/oocyst/cyst) from Entamoeba histolytica/dispar, a parasite common in human settlements of the Amhara region. In crop areas, subjects spent less time grooming but engaged in lower rates of intense aggression (in partial agreement with prediction 2). We speculate that the reduction in social behavior may be a tactic adopted by geladas to minimize the likelihood of detection and maximize food intake while foraging in crops.

Further away with dental microwear analysis: Food resource partitioning among Plio-Pleistocene monkeys from the Shungura Formation, Ethiopia

This study aims at improving dietary discrimination among primates through a new analytic approach of dental microwear texture analysis integrating a surface sampling on facets of both phase I and II of mastication. The surface sampling is applied on these two types of molar facets on 104 specimens belonging to four extant cercopithecids, and on 207 Plio-Pleistocene specimens representing four taxa from the Shungura Formation, Ethiopia. The extant species, including Colobus guereza, Theropithecus gelada, Papio hamadryas, Chlorocebus aethiops, compose a model covering a wide range of feeding ecology from leaf-eating through grass-eating habits to opportunistic habits.A principal component analysis built with a selection of the most discriminant variables and extant species as a model displays that the two facets contribute equally to the dispersion of individuals and to the between-species differences. Also, most contributing variables along the components are not central values of texture parameters (mean and median of the parameters measured on subsurfaces or a single value for the whole surface) but rather statistics of their dispersion (percentiles) and distribution (kurtosis, skewness).Once the fossil specimens are inserted into the extant species model, the two large-bodied colobines, Paracolobus and Rhinocolobus, are found to differ from the extant Colobus guereza, one of the most leaf-eating colobines. This highlights ecological diversity among early African colobines. Besides, the analysis tracks between-genus as well as temporal differences between the extinct species of papionins, attesting of a low ecological overlapping between Theropithecus and non-theropith papionins, notably after 2.4 Ma. No significant difference was found between T. brumpti, T. oswaldi, Theropithecus sp. supporting similar feeding habits with the present-day gelada, at least from 2.9 Ma onwards.

Let’s unite in play! Play modality and group membership in wild geladas

Two of the main hypotheses put forth to explain the function of immature social play are the Social Skill Hypothesis and the Motor Training Hypothesis focussing on whether play can improve social competence to develop cooperative social networks or physical abilities to outcompete others, respectively. Here, we tested these hypotheses on a monkey species, the wild gelada (Theropithecus gelada) from the Kundi plateau, Ethiopia. This species is organized in bands divided in One-Male Units (OMUs), united only via social play. Immatures form ‘play units’ in which individuals from the same and different OMUs interact. We analysed the potential differences between inter- and intra-OMU play to verify which of the two hypotheses (Social Skill or Motor Training Hypothesis) best explains the function of play in geladas. We analysed 527 video-recorded social play sessions and found mixed support for both hypotheses. In agreement with the Social Skill Hypothesis, we found that play in geladas shows scarce social canalization being similarly distributed across age, sex and group membership. In line with the Motor Training Hypothesis, we detected higher levels of competition (shorter and more unbalanced sessions) in inter-OMU compared to intra-OMU play. Hence, in geladas play can be a tool for both the development of social relationships and the improvement of the physical skills necessary to cope with either future mates or competitors. In conclusion, neither hypothesis can be discarded and both hypotheses concur in explaining why immature geladas peculiarly form ‘play units’ embracing both ingroup and outgroup members.

Seasonal shifts in the gut microbiome indicate plastic responses to diet in wild geladas

BackgroundAdaptive shifts in gut microbiome composition are one route by which animals adapt to seasonal changes in food availability and diet. However, outside of dietary shifts, other potential environmental drivers of gut microbial composition have rarely been investigated, particularly in organisms living in their natural environments.ResultsHere, we generated the largest wild nonhuman primate gut microbiome dataset to date to identify the environmental drivers of gut microbial diversity and function in 758 samples collected from wild Ethiopian geladas (Theropithecus gelada). Because geladas live in a cold, high-altitude environment and have a low-quality grass-based diet, they face extreme thermoregulatory and energetic constraints. We tested how proxies of food availability (rainfall) and thermoregulatory stress (temperature) predicted gut microbiome composition of geladas. The gelada gut microbiome composition covaried with rainfall and temperature in a pattern that suggests distinct responses to dietary and thermoregulatory challenges. Microbial changes were driven by differences in the main components of the diet across seasons: in rainier periods, the gut was dominated by cellulolytic/fermentative bacteria that specialized in digesting grass, while during dry periods the gut was dominated by bacteria that break down starches found in underground plant parts. Temperature had a comparatively smaller, but detectable, effect on the gut microbiome. During cold and dry periods, bacterial genes involved in energy, amino acid, and lipid metabolism increased, suggesting a stimulation of fermentation activity in the gut when thermoregulatory and nutritional stress co-occurred, and potentially helping geladas to maintain energy balance during challenging periods.ConclusionTogether, these results shed light on the extent to which gut microbiota plasticity provides dietary and metabolic flexibility to the host, and might be a key factor to thriving in changing environments. On a longer evolutionary timescale, such metabolic flexibility provided by the gut microbiome may have also allowed members of Theropithecus to adopt a specialized diet, and colonize new high-altitude grassland habitats in East Africa.1akjfNgEHq-cf4GgXinJf8Video abstract

Primate Reproduction: When Timing Is Everything

In species with intense male competition, reproducing at the wrong time can have dire consequences for females. A new study of wild gelada monkeys finds that females delay or accelerate puberty to moderate the risks of inbreeding and infanticide.

Male-Mediated Maturation in Wild Geladas

The timing of female maturation in wild mammals is often constrained by ecological variables that relate to food acquisition. However, maturational timing in female mammals can also respond to social variables. Specifically, the arrival of novel males can accelerate maturation while the presence of related males can inhibit it. Despite studies on more than two dozen mammalian taxa in captivity, evidence for male-mediated maturation has not been systematically demonstrated in any wild population. Here, we report the first evidence of male-mediated maturation in a wild primate, the gelada (Theropithecus gelada). After the arrival of a new breeding male in the group (a male takeover), young females were three times more likely to mature. We then examined these takeover-associated maturations in more detail: some were earlier than expected (a presumptive "Vandenbergh effect," or male-accelerated maturation), some were at the expected age for the average female gelada, and some were later than expected (a presumptive "inbreeding avoidance delay," or father-induced reproductive suppression). An examination of fecal estrogens, which rise just before visible signs of maturation in this species, revealed that male takeovers induced a surge in estrogens for immature females of all ages-even females that did not mature. These are the first data to demonstrate that specific males are associated with the onset of maturation in a wild primate and to provide a possible mechanism for this change. These results suggest that all male-mediated maturation (whether accelerated, on-time, or delayed) may be governed by similar neuroendocrine processes.

Threats to Gelada Baboons (Theropithecus Gelada) in and Around Jer Silase Monastry in Amhara National Regional State, North Shoa Zone, Ethiopia

The study was carried out in and around Jer Silase Monastry in Amhara National regional State, North Shoa Zone, from July 2019 to February 2020. The study aimed to determine threats of gelada baboons. The data was collected through questionnaires, household survey, direct observation and focus group discussions. Sample size was determined with Israel’s formula (1992). Statistical Package for Social Sciences (SPSS) version 20 Computer software program, using descriptive statics and chi-square test to compare responses of respondents. The attitudes of literate respondents and illiterate respondents towards gelada baboons were highly significant difference (

First evidence of stone handling in geladas: From simple to more complex forms of object play

Stone Handling (SH) is a solitary object play behaviour that can vary from simple exploratory actions to more complex manipulations. So far, among primates, this behaviour has been exclusively reported in macaques. We collected data on 62 geladas (Theropithecus gelada) housed at the NaturZoo (Rheine, Germany). We found that about 70% of subjects belonging to all age- and sex-classes engaged in SH. Due to their exceptional manipulative skills (the highest opposability index among nonhuman primates) and propensity to play, geladas are a good model species to test hypotheses on the function of this form of object play. While the frequency of SH tended to decrease with age of the player, the duration of each session and its complexity tended to increase in juveniles/subadults and adults compared to infants. This age-related variation in terms of frequency, duration and complexity suggests that, in agreement with the motor training hypothesis, SH could have a role in the neural–motor development of immature subjects and a basic function in stimulating neurogenesis and maintaining the psychological well-being of adults. In all age classes, the frequency of SH did not vary across pre-feeding, feeding and non-feeding conditions. Hence, our data do not support the misdirected foraging hypothesis, which predicts that animals engage in SH to anticipate food provisioning. In conclusion, our study reveals, for the first time, the presence of SH outside the genus Macaca and attempts to delineate possible functions of the behaviour in geladas. Since the hypotheses tested cannot be mutually exclusive, long-term studies of SH across individuals’ lifetimes in both captive and wild groups of geladas are needed to clarify the proximate and ultimate functions of the behaviour in this species of Papionini. Finally, long-term studies could also provide some important indications about the cultural nature and social transmission of SH in a taxonomic group outside the Macaca genus.

Geographic distribution of microsatellite alleles in geladas (Primates, Cercopithecidae): Evidence for three evolutionary units

AbstractThe subspecific taxonomy and distribution of geladas (Theropithecus gelada Rüppell, 1835) remains uncertain. Recent molecular studies based on mitochondrial sequence data revealed a geographically structured, three‐deme population, suggesting that there are three evolutionary units of geladas. However, mitochondrial distributions do not always recover population relationships, particularly in taxa with a complex history of isolation and gene flow. We therefore analysed the nuclear genetic population structure of the global gelada population based on 20 microsatellite loci in 43 samples from across its geographic range. FST values, a STRUCTURE analysis and a principal coordinate analysis (PCoA) confirmed the three‐deme population structure corresponding to the mitochondrial population structure. Therefore, our analyses provide additional support for three evolutionary units in geladas, corresponding to (a) a northern (north of Lake Tana, primarily in the Simien Mountains, previously classified as Theropithecus gelada gelada Rüppell, 1835), (b) a central (between Addis Ababa and the highlands east of Lake Tana, previously classified as Theropithecus gelada obscurus Heuglin, 1863) and (c) a southern (south of the Rift Valley, previously tentatively classified as Theropithecus gelada arsi Shotake et al., 2016, Anthropological Science, 124, 157) population. These results pave the way for future conservation decisions and highlight that the gelada population boundaries need more fine‐grained genetic sampling and phenotypic analyses, in particular for their taxonomic ranking.