The concept of dominance has contributed greatly to our understanding of social structure in animals. Over the past three decades, however, a variety of concepts and definitions of dominance have been introduced, leading to an ongoing debate about the usefulness and meaning of the concept. Criticisms aimed at one definition of dominance do not necessarilly apply to other definitions. Existing definitions can be structural or functional, refer to roles or to agonistic behaviour, regard dominance as a property of individuals or as an attribute of dyadic encounters, concentrate on aggression or on the lack of it, and be based either on theoretical constructs or on observable behaviour. Thirteen definitions of dominance are reviewed, and their usefulness assessed with respect to their descriptive value. The predictive and explanatory values of definitions are specific to the questions asked in each particular study and are not considered as criteria to judge the usefulness of the dominance concept. By virtue of its high descriptive value, the original definition of dominance by SCHJELDERUPP-EBBE (1922, Z.Psychol. 88: 226-252) emerged as the basis to formulate a structural definition with wide applicability and which reflects the essence of the concept: Dominance is an attribute of the pattern of repeated, agonistic interactions between two individuals, characterized by a consistent outcome in favour of the same dyad member and a default yielding response of its opponent rather than escalation. The status of the consistent winner is dominant and that of the loser subordinate. Dominance status refers to dyads while dominance rank, high or low, refers to the position in a hierarchy and, thus, depends on group composition. Dominance is a relative measure and not an absolute property of individuals. The discussion includes reference to the heritability of dominance, application of dominance to groups rather than individuals, and the role of individual recognition and memory during agonistic encounters.
Injury in male baboons (Papio cynocephalus) was investigated as an indicator of damaging fights in order to provide a framework for analyses of conflict resolution and dynamics of agonistic competition in primates. The vast majority of wounds were canine slashes resulting from intraspecific face-to-face combat. Wounds were more common in males than females. In males they concentrated on the right side of anterior parts of the body, principally the head. Wounds took on average three weeks to heal. Aggressive conflicts represented 10% of all interactions between males. Less than 1% of aggressive contests led to injury. The individual rate of injury from fights with other males was on average once every 1.5 months. The winner of damaging fights was sometimes the wounded individual. The number of wounds per damaging fight was not related in a simple way to the presence of proceptive females or to recent immigration events. Four fights yielding the highest number of injuries, however, involved recent immigrations or attempts to immigrate by adult males in their prime. Contexts of male injury observed during infliction include challenges to the resident alpha male by newcomers, intertroop encounter, fights over proceptive females or unusual foods, redirected aggression, defense of a female and a fight unrelated to any obvious resource. This study and anecdotal reports from the literature point at various implications of injury to male baboons, including physical impairments which can constrain feeding efficiency, limit access to resting sites and safe retreats, cause a drop in dominance rank, jeopardize mating success and even result in death. Severely injured males typically reduce interaction rates, retreat to the periphery of the troop or emigrate temporarily. Although most wounds are small and heal well, the potentially high costs of injury probably exercise strong selection pressure on contestants for means of peaceful conflict resolution, given that during fights both baboons risk injury irrespective of their competitive abilities. The potential fitness consequences of inflicted injury can explain the evolution of the formidable canine weaponry of some male primates.
A nationwide survey that included personal interviews in 1,021 households studied the incidence, species, and numbers of nonhuman animals kept in Costa Rican households. A total of 71% of households keep animals.The proportion of households keeping dogs (53%) is 3.6 higher than the proportion of households keeping cats (15%). In addition to the usual domestic or companion animals kept in 66% of the households, 24% of households keep wild species as pets. Although parrots are the bulk of wild species kept as pets, there is vast species diversity, including other birds, reptiles, mammals, amphibians, fishes, and invertebrates - typically caught in their natural habitat to satisfy the pet market. The extraction from the wild and the keeping of such animals is by-and-large illegal and often involves endangered species. Costa Ricans, in a conservative estimate, keep about 151,288 parrots as pets. More than half the respondents have kept a psittacid at some point in their lives. Pet keeping is a common practice in Costa Rican society, and its incidence is high by international standards