Julia Lehmann

The juvenile life stage is crucial in primates, yet the behavior and diet of juveniles is an understudied area of primatology. Compared with adults, considerably less is known about wild juvenile primate development, particularly that of western lowland gorillas ( Gorilla gorilla gorilla ). While sex differences in diet and time budgets are well studied in adults, work remains to be done on how age and sex influence juvenile behavior. Here, we use data from nine immature reintroduced western lowland gorillas to fill some of this knowledge gap. We found that the immature gorillas spent most time feeding, followed by resting. Younger juveniles spent less time resting than older individuals, instead spending more time in self-play compared with older juveniles and more time in locomotion than subadults. The group had a varied diet as would be expected for western lowland gorillas; predominantly eating stems, flowers/leaves and fruit, with subadults eating more stems compared to younger individuals. Sex was found to have little influence on either behavior or diet. Additionally, behavioral and dietary diversity were calculated in order to describe the diversity of immature western lowland gorilla behavior. There were no age or sex differences found among this group of individuals, suggesting behavioral repertoire and diet may be influenced by those in their social group. The wider aim of this study is to provide insights into immature western lowland gorilla behavior and diet in the wild while also contributing to understanding of the post-release period for rehabilitated primates.

The ability to optimize social behavior to varying socioecological circumstances has been termed “social competence” and relies on behavioral plasticity. Behavioral syndromes, i.e. consistent individual differences in intraindividual correlations among behavioral traits, appear to be a constraint on social competence, yet studies exploring this have largely been limited to experimental laboratory settings. Here, we tested the importance of behavioral syndromes to social competence in wild Barbary macaques ( Macaca sylvanus ), an endangered primate with established links between positive social relationships and survival. We studied two groups ( n = 27 individuals) in which behavioral syndrome phenotypes were established in a previous study. Individuals with lower scores for the “excitable” phenotype (roughly equivalent to the “shy-bold” axis in other studies) showed greater plasticity compared to more “excitable” (i.e., “bolder”) individuals in affiliative responses to the immediate social environment, being more likely to initiate grooming with larger numbers of conspecific bystanders present. Less excitable individuals increased their grooming social network connectivity to a greater degree compared to more excitable individuals in periods of higher anthropogenic pressure. During colder weather, less excitable individuals concentrated their grooming network into fewer ties, whereas more excitable individuals slightly increased their number of connections. Any changes in network connectivity in relation to socioecology were small, reflecting the fact that stability in social network position is a common phenomenon in various taxa. Overall, we show that behavioral syndrome phenotypes influence plasticity in affiliative behavior and thus may be a key factor in individual responses to the rapidly changing socioecologies of the Anthropocene.

Over six decades of research on wild baboons and their close relatives (collectively, the African papionins) have uncovered substantial variation in their behavior and social systems. While most papionins form discrete social groups (single-level societies), a few others form small social units that are nested within larger supergroups (multi-level societies). These two systems are generally thought to be qualitatively distinct, but data from wild populations increasingly suggest that there may be areas of overlap. To quantify this potential gradient in social structure, a more systematic, comparative analysis is needed. Here, we constructed a database of behavioral and demographic records spanning 135 group-years, 28 social groups, 13 long-term field studies, and 11 species to quantify variation in grooming network structure, and identify the individual and dyadic properties (e.g., kinship and social status effects) that underlie this variation. Consistent with accumulating observations in the field, the single-level species could be divided into two categories: cohesive and cliquish . Cohesive single-level networks were dense, kin-biased, and moderately rank-structured, while cliquish single-level networks were more differentiated, slightly more kin-biased, and strongly rank-structured. As expected, multi-level networks were very modular and shaped by females’ ties to specific dominant males but varied in their kin biases. Taken together, these data suggest that (i) kin and rank biases are widespread but vary in their strength; (ii) male-centered subgroups are exclusive to multi-level systems; and (iii) increases in network modularity can emerge in response to heightened nepotism and male-centered clustering. SIGNIFICANCE STATEMENT: What forces explain variation in primate societies? While kinship and dominance shape the social lives of many of our close relatives, it is unclear how their effects differ across species. Using a new database comprising decades of field research, we found that baboons and their close relatives fell into three general patterns: one in which groups were cohesive, kin-biased, and moderately rank-biased, another in which groups were more cliquish and nepotistic, and a third in which groups were divided into clusters centered on dominant males. Distinct primate societies may thus reflect differences in the strength of females’ nepotistic biases and the degree of males’ social influence.

There is a vast and ever‐accumulating amount of behavioural data on individually recognised animals, an incredible resource to shed light on the ecological and evolutionary drivers of variation in animal behaviour. Yet, the full potential of such data lies in comparative research across taxa with distinct life histories and ecologies. Substantial challenges impede systematic comparisons, one of which is the lack of persistent, accessible and standardised databases. Big‐team approaches to building standardised databases offer a solution to facilitating reliable cross‐species comparisons. By sharing both data and expertise among researchers, these approaches ensure that valuable data, which might otherwise go unused, become easier to discover, repurpose and synthesise. Additionally, such large‐scale collaborations promote a culture of sharing within the research community, incentivising researchers to contribute their data by ensuring their interests are considered through clear sharing guidelines. Active communication with the data contributors during the standardisation process also helps avoid misinterpretation of the data, ultimately improving the reliability of comparative databases. Here, we introduce MacaqueNet, a global collaboration of over 100 researchers (https://macaquenet.github.io/) aimed at unlocking the wealth of cross‐species data for research on macaque social behaviour. The MacaqueNet database encompasses data from 1981 to the present on 61 populations across 14 species and is the first publicly searchable and standardised database on affiliative and agonistic animal social behaviour. We describe the establishment of MacaqueNet, from the steps we took to start a large‐scale collective, to the creation of a cross‐species collaborative database and the implementation of data entry and retrieval protocols. We share MacaqueNet's component resources: an R package for data standardisation, website code, the relational database structure, a glossary and data sharing terms of use. With all these components openly accessible, MacaqueNet can act as a fully replicable template for future endeavours establishing large‐scale collaborative comparative databases.

Background Eighty-eight thousand fall accidents occur each year in Switzerland among people aged 65 and over, which cause a lot of personal suffering and economic costs Beratungsstelle für Unfallverhütung BFU, 2019). The exercise at home program “DomiGym - Bewegungsangebot zu Hause” (in short: DomiGym) of Pro Senectute Switzerland aims to maintain mobility, counteract the risk of falls and promote social contacts as well as social participation and psychosocial health. Vulnerable, elderly people enjoy with DomiGym an adapted, regular training program focused on strength and balance, in their own homes or in their neighborhoods. Methodology The implementation and effects of the DomiGym offers in the cantons of Zug and Zurich were evaluated using various methodological approaches: tests of strength (Chair-Stand-Test; Mehmet et al., 2019), of balance (Modified Romberg; Agrawa et al., 2011) and of functional mobility (Timed-Up-and-Go-Test; Marks, 2016) as well as written surveys of participants (based on standardized scales used in the Swiss Health Survey). Results On average participants reduced fall risk and improved functional mobility and leg strength (p < 0.05). In a subsample of the canton of Zug, the Timed-Up-and-Go-Test (functional mobility and fall risk) improved by an average of 2.3 seconds (p < 0.005) and the balance test (Romberg) improved by 1.8 seconds (p = 0.005). Over the course of a training series the reduction in fall risk proved clinically relevant in both cantons. Scores on the Timed-Up-and-Go-Test fell on average below the threshold of 13.5 seconds discriminating between fallers and non-fallers. Chair-stand test: Participants improved on average from an initial very high fall risk to an increased fall risk (below 15 seconds). In fact the subsample of canton Zug improved by an average of 3.96 seconds (clinically relevant with regard to the reduction of falls) and the subsample of canton Zurich improved by an average of 2.17 seconds (approximately clinically relevant; threshold value 2.3 seconds; Meretta et al., 2006). DomiGym improved the general health (67%) of most participants and either maintained the original walking level (80%) or even improved it (15%). The majority of DomiGym participants do gymnastic exercises at least weekly outside of DomiGym training. DomiGym participants positively change their movement behavior in everyday life. Conclusions Pro Senectute’s DomiGym reaches older people who cannot or do not want to attend out-of-home physical activity programs. The implementation of DomiGym improves the physical functions of leg strength, functional mobility, and balance, as well as the risk of falls in vulnerable elderly people. It can be assumed that DomiGym reduces the frequency of falls in the long term, contributes to the preservation of mobility and independence in everyday life, including a longer stay in their own homes. References Agrawa, Y., Carey, J. P., Hoffman, H. J., Sklare, D. A., & Schubert, M. C. (2011). The modified Romberg balance test: Normative data in US adults. Otology & Neurotology, 32(8), 1309-1311. https://doi.org/10.1097/MAO.0b013e31822e5bee Beratungsstelle für Unfallverhütung BFU. (2019). Status 2019: Statistik der Nichtberufsunfälle und des Sicherheitsniveaus in der Schweiz. Strassenverkehr, Sport, Haus und Freizeit [Status 2019: Statistics on non-occupational accidents and safety levels in Switzerland. Road traffic, sports, home and leisure]. BFU. https://doi.org/10.13100/bfu.2.360.01 Marks, D. (2016). Aufstehen – Gehen – Umdrehen – Gehen – Hinsetzen – Timed-up-and-go-Test [Stand up – walk – turn around – walk – sit down – timed-up-and-go test]. physiopraxis, 14(07/08), 56-57. https://doi.org/10.1055/s-0042-108951 Mehmet, H., Yang, A. W. H., & Robinson, S. R. (2019). What is the optimal chair stand test protocol for older adults? A systematic review. Disability and Rehabilitation, 42(20), 2828-2835. https://doi.org/10.1080/09638288.2019.1575922 Meretta, B. M., Whitney, S. L., Marchetti, G. F., Sparto, P. J., & Muirhead, R. J. (2006). The five times sit to stand test: Responsiveness to change and concurrent validity in adults undergoing vestibular rehabilitation. Journal of Vestibular Research, 16(4-5). 233-243. https://doi.org/10.3233/VES-2006-164-510

In recent years, there has been considerable interest in investigating how animal social structure is affected by the loss of individuals. This is often achieved using simulations that generate predictions regarding how the removal of ‘key’ individuals from a group affects network structure. However, little is known about the effects of such removals in wild and free-ranging populations, particularly the extent to which naturally occurring mortality events and the loss of a large proportion of individuals from a social group affects the overall structure of a social network. Here, we used data from a population of wild Barbary macaques (Macaca sylvanus) that was exposed to an exceptionally harsh winter, culminating in the death of 64% of the adults from two groups. We analysed how social interaction patterns among surviving individuals were affected by the natural loss of group members using social networks based on affiliative (i.e., grooming) and aggressive social interactions. We show that only the structure of the pre-decline grooming networks was conserved in the post-decline networks, suggesting that grooming, but not aggression networks are resilient against the loss of group members. Surviving group members were not significantly different from the non-survivors in terms of their affiliative and agonistic relationships, and did not form assorted communities in the pre-decline networks. Overall, our results suggest that in primates, patterns of affiliative interactions are more resilient to changes in group composition than aggressive interaction patterns, which tend to be used more flexibly in new conditions.

It is widely believed that there is strong association between physiological stress and an individual's social status in their social hierarchy. This has been claimed for all humans cross-culturally, as well as in non-human animals living in social groups. However, the relationship between stress and social status has not been explored in any egalitarian hunter–gatherer society; it is also under investigated in exclusively female social groups. Most of human evolutionary history was spent in small, mobile foraging bands of hunter–gatherers with little economic differentiation – egalitarian societies. We analysed women's hair cortisol concentration along with two domains of women's social status (foraging reputation and popularity) in an egalitarian hunter–gatherer society, the Hadza. We hypothesized that higher social status would be associated with lower physiological indicators of stress in these women. Surprisingly, we did not find any association between either foraging reputation or popularity and hair cortisol concentration. The results of our study suggest that social status is not a consistent or powerful predictor of physiological stress levels in women in an egalitarian social structure. This challenges the notion that social status has the same basic physiological implications across all demographics and in all human societies.

Intergroup encounters are common in nonhuman primates and can vary from affiliative to aggressive. We extracted data from the literature to test five different hypotheses: 1) where there are group size differences between opposing groups, whether the larger group is more likely to win an intergroup encounter than the smaller group; 2) whether the likelihood of a group engaging in aggressive intergroup encounters increases with group size; and 3–5) whether dominant, older individuals, and/or males are more likely to participate aggressively in intergroup encounters than subordinate, younger individuals and/or females. Our data set comprised 52 studies on 31 primate species (3 lemur species, 5 New World monkeys, 19 Old World monkeys, and 4 apes). We found that the larger group is more likely to win an encounter against a smaller group than vice versa. We found no significant relationship between group size and propensity to be aggressive during intergroup encounters. We found weak/no support for the effect of age, dominance rank, and sex on the frequency of aggression displayed toward outgroup individuals during intergroup encounters. Species- and population-specific differences in inter- and intragroup competition and in the degree of the unequal distribution of resources across group members may explain why age, dominance rank, and sex are not strong predictors of aggression during intergroup encounters.

Behavioural syndromes are a well-established phenomenon in human and non-human animal behavioural ecology. However, the mechanisms that lead to correlations among behaviours and individual consistency in their expression at the apparent expense of behavioural plasticity remain unclear. The ‘state-dependent' hypothesis posits that inter-individual variation in behaviour arises from inter-individual variation in state and that the relative stability of these states within an individual leads to consistency of behaviour. The endocrine stress response, in part mediated by glucocorticoids (GCs), is a proposed behavioural syndrome-associated state as GC levels are linked to an individual's behavioural responses to stressors. In this study, in wild Barbary macaques (Macaca sylvanus), consistent inter-individual differences were observed in both sexes for GC activity (faecal glucocorticoid, fGC concentrations), but not GC variation (coefficient of variation in fGC concentrations). The expression of the behavioural syndrome ‘Excitability' (characterized by the frequencies of brief affiliation or aggressive interactions) was related to GC activity in males but not in females; more ‘excitable' males had lower GC activity. There was no relationship in females between any of the behavioural syndromes and GC activity, nor in either sex with GC variation. The negative relationship between GC activity and Excitability in males provides some support for GC expression as a behavioural syndrome-generating state under the state-dependent framework. The absence of this relationship in females highlights that state-behavioural syndrome associations may not be generalizable within a species and that broader sex differences in state need to be considered for understanding the emergence and maintenance of behavioural syndromes.