Feeding Competition and Agonistic Relationships Among Bwindi Gorilla beringei

Testing predictions of socioecological models, specifically that the types of feeding competition and social relationships female primates exhibit are strongly influenced by the distribution, density, and quality of food resources, requires studies of closely related populations of subjects living under different ecological conditions. I examined feeding competition and the resulting female social relationships in mountain […]

Effect of mares’ dominance rank on suckling behaviour in the loose housed domestic horses

Suckling is a main part of maternal investment in equids. The suckling period is crucial for adequate physical as well as psychical development of the foal. The rank of the mother and her aggressiveness could be factors responsible for later reproductive or social success of the foal. We hypothesised that under conditions characterized by balanced […]

Assessing dominance hierarchies: validation and advantages of progressive evaluation with Elo-rating


Factors affecting aggression among females in captive groups of rhesus macaques (Macaca mulatta)

Captive groups of primates often exhibit higher rates of aggression than wild, free-ranging groups. It is important to determine which factors influence aggression in captivity because aggression, particularly intense aggression, can be harmful to animal health and well-being. In this study, we investigated the effect of ground substrate as well as season, rank, age, and […]

Behavioral style, dominance rank, and urinary cortisol in young chimpanzees (Pan troglodytes)

Remarkable individual variation in primate personalities is evident to those who study them, but the concept of ‘personality’ has nevertheless received little attention in the nonhuman primate literature. In this study, I introduce a novel implementation of a method to quantify primate personality or behavioral style based on ethological observations and use it to test […]

The physiology of cooperative breeding in a rare social canid; sex, suppression and pseudopregnancy in female Ethiopian wolves

Ethiopian wolves, Canis simensis, differ from other cooperatively breeding canids in that they combine intense sociality with solitary foraging, making them a suitable species in which to study the physiology of cooperative breeding. The reproductive physiology of twenty wild female Ethiopian wolves (eleven dominant and nine subordinate) in Ethiopia’s Bale Mountains National Park was studied […]

Effects of restraint with or without blinds at the feed barrier on feeding and agonistic behaviour in horned and hornless goats

The strict dominance hierarchy in goats bears the risk of low-ranking goats not getting adequate access to feed, especially for goats in small groups. The aim of our study was to test the effect of restraint in headlocks with and without blinds at the feed barrier on feeding and agonistic behaviour in horned and hornless […]

Social bonds in female baboons: the interaction between personality, kinship and rank

Previous analyses indicate that female baboons that form strong and stable social bonds reproduce more successfully than others, and that some elements of females’ personalities are associated with the tendency to form close social bonds. Here we use a new method to confirm that females’ personalities were stable over time, although not fixed, and that […]

Social status drives social relationships in groups of unrelated female rhesus macaques

Strong social relationships confer health and fitness benefits in a number of species, motivating the need to understand the processes through which they arise. In female cercopithecine primates, both kinship and dominance rank are thought to influence rates of affiliative behaviour and social partner preference. Teasing apart the relative importance of these factors has been […]

Grooming, social rank and ‘optimism’ in tufted capuchin monkeys: a study of judgement bias

Studying the emotional consequences of social behaviour in nonverbal animals require methods to access their emotional state. One such method is provided by cognitive bias tests. We applied a judgement bias test to tufted capuchin monkeys, Sapajus sp., to evaluate (1) whether receiving grooming was associated with a short-term increase in ‘optimism’ (that is, a […]