The relation of rank to physiological state in Cnemidophorus sexlineatus dominance hierarchies

The six-lined racerunner, Cnemidophorus sexlineatus, maintains dominance hierarchies in captivity. Trios of ♂ ♂ were observed to determine the relation of hierarchy rank to physiological state and behavior. Rank was closely related to body weight and aggressiveness. High ranking ♂ ♂, unlike low ranking ♂ ♂, readily tried to mate with ♀ ♀. Anatomical examination […]

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


Effect of Unknown Relationships on Linearity, Steepness and Rank Ordering of Dominance Hierarchies: Simulation Studies Based on Data from Wild Monkeys

The presence of unknown dyadic relationships is a common problem in constructing dominance hierarchies for groups of social animals. Although previously acknowledged, the influence of unknown relationships on hierarchy measures like linearity and steepness has not been studied in detail. Using real data-sets from four groups of wild monkeys, we illustrate how unknown relationships affect […]

Assessment of Dominance Hierarchy Through Urine Scent Marking and its Chemical Constituents in Male Blackbuck Antelope cervicapra, A Critically Endangered Species

In ungulates the process of chemical communication by urinary scent marking has been directly related to reproductive dominance, territorial defense and proximity to resources. The differences in the frequency of urine marking and chemical composition of urine of males Antelope cervicapra before, during and after the dominance hierarchy period were assessed. The variations in the […]

Effects of isotocin on social responses in a cooperatively breeding fish

Oxytocin and its nonmammalian homologues play an important role in modulating a diverse array of social behaviours. Recently, it has been suggested that one of the key functions of oxytocin is to direct attention towards socially relevant stimuli, increase social motivation and guide social decision making. Here, we test whether an exogenous increase in isotocin […]

Network structure is related to social conflict in a cooperatively breeding fish

The nature of individual social interactions can have a profound influence on group structure and function. Here, we use social network analysis to examine patterns of dominance interactions and spatial associations in 14 captive social groups of the cooperatively breeding cichlid, Neolamprologus pulcher. In this cichlid, social groups are composed of a dominant breeding pair […]

The pig’s nose and its role in dominance relationships and harmful behaviour

Affiliative behaviour may have an essential role in many behavioural processes. Gently nosing between group members occurs in almost all social behavioural processes of pigs (Sus scrofa), but the reasons for its performance are unclear. We examined whether nosing between pigs was related to dominance relationships or harmful behaviours such as manipulation of the tail […]

Establishment of a Captive All-male Group of Proboscis Monkey (Nasalis larvatus) at the Singapore Zoo

Surplus male proboscis monkeys at the Singapore Zoo pose a considerable problem for maintenance and maximizing of exhibition potential. In 2008, a new exhibit was constructed to house and display a group of six proboscis monkey males born in Singapore Zoo. To document and monitor the all-male group establishment in the new exhibit, we conducted […]

Individual recognition in a wild cooperative mammal using contact calls

Many of the mechanisms advanced to explain the evolution of intraspecific cooperative behaviour, such as reciprocity or social prestige, hinge on an animal’s ability to recognize individual group members. However, ‘true’ individual recognition, between adult group members, has never been demonstrated in a cooperatively breeding bird or mammal species. We tested whether a wild cooperative […]

Behavioural patterns established during suckling reappear when piglets are forced to form a new dominance hierarchy

Early life experiences considerably influence the behavioural development of the animals in which the social environment plays a crucial role. Neonatal piglets experience intense social (including aggressive) interactions when compete with their littermates for the access to teats on the sow’s udder. Competition among piglets is not of equal intensity at all parts of the […]