Measuring and testing the steepness of dominance hierarchies

In the analysis of social dominance in groups of animals, linearity has been used by many researchers as the main structural characteristic of a dominance hierarchy. In this paper we propose, alongside linearity, a quantitative measure for another property of a dominance hierarchy, namely its steepness. Steepness of a hierarchy is defined here as the […]

Cache spacing patterns and reciprocal cache theft in New Zealand robins

We quantified cache spacing patterns, cache retrieval rates and rates of cache theft in New Zealand robins, Petroica australis. In a field experiment we presented wild birds with a superabundant supply of mealworms. Trials were conducted on competitively dominant males and subordinate females, both when birds were alone and when they were accompanied by their […]

Behavioral, physiological, and morphological components of dominance and mate attraction in male green iguanas

Abstract 10.1002/zoo.1430110304.abs This study investigated the morphological, physiological, and behavioral components of social dominance important for mate attraction in male green iguanas (Iguana iguana). A group of 9 male and 11 female adult green iguanas was studied in a large semi-natural enclosure during one reproductive season (October–January). Four of the nine males never initiated aggressive […]

The relationship between dominance, corticosterone, memory, and food caching in mountain chickadees (Poecile gambeli)

It has been hypothesized that in avian social groups subordinate individuals should maintain more energy reserves than dominants, as an insurance against increased perceived risk of starvation. Subordinates might also have elevated baseline corticosterone levels because corticosterone is known to facilitate fattening in birds. Recent experiments showed that moderately elevated corticosterone levels resulting from unpredictable […]

Extension of reproductive suppression by pheromonal cues in subordinate female marmoset monkeys, Callithrix jacchus

Pheromonal signals from the dominant female marmoset monkey were implicated in maintaining the suppression of LH secretion and ovulation in socially subordinate females. When subordinate, and reproductively suppressed, female marmoset monkeys were removed from their group without scent contact with their dominant females, subordinate females in control group 1 (N = 8) and control group […]

Rhesus Macaques (Macaca mulatta) Categorize Unknown Conspecifics According to Their Dominance Relations

The authors trained 3 adult male rhesus macaques (Macaca mulatta) to categorize pairs of unknown conspecifics presented in a video according to the dominance status of the videotaped monkeys. The subjects were trained to choose the dominant monkey for a category of films (e.g., films showing 1 monkey chasing another); then, new films were presented […]

Following and Joining the Informed Individual in Semifree-Ranging Tonkean Macaques (Macaca tonkeana)

The authors investigated whether Tonkean macaques (Macaca tonkeana) can distinguish between 2 group mates with different knowledge and improve their foraging performance. The subjects were 8 young individuals belonging to a group raised in a 2-acre park. The authors carried out 192 tests in which subgroups of 3 individuals were released in a food search […]

The effect of environmental enrichment on play behaviour in white-lipped peccaries (Tayassu pecari)

Herds of white-lipped peccary (Tayassu pecari) have historically been kept in captivity in order to replace stocks lost to hunting however the lack of knowledge regarding their species-typical behaviour remains an impediment to understanding their captive needs. Environmental enrichment has been suggested as an efficient way of decreasing aggression and apathy as well as increasing […]

Behavioral Correlates of Post-Breeding Weight Change in a Captive Flock of American Flamingos (Phoenicopterus ruber ruber)

In a captive flock of American flamingos (Phoenicopterus ruber ruber), a pattern of weight loss after the breeding season was observed in the majority of individuals of both sexes, but weights eventually stabilized after several months. Social dominance (as determined by a 6-month behavioral study) was a highly significant predictor of early post-breeding weight loss, […]

Winning and losing in public: Audiences direct future success in Japanese quail

Abstract Among vertebrates, winning a fight enhances the probability of future victories and vice versa and the role of post-conflict testosterone in mediating this ‘winner effect’ is widely accepted. In a series of staged fights of Japanese quail (Coturnix japonica) we tested both opponents’ pre-fight and post-conflict testosterone, behavior and dominance status after returning to […]