Abstract: The communication of aggressive motivation or fighting ability has important fitness consequences for competing animals. Selection should favour rapid and honest communication between opponents to settle dominance relationships while avoiding prolonged and intense fighting. We investigated factors that influence fighting strategies and contest outcomes in female house finches, Carpodacus mexicanus, specifically focusing on the following questions. (1) What social contexts trigger an aggressive response? (2) Does body size and condition contribute to female fighting ability? (3) Do contextual factors, such as mate presence, nest status, nest proximity, and site experience contribute to fighting motivation? (4) Does contest intensity and duration increase as the differences in fighting ability between opponents decrease? (5) What is the relative contribution of fighting ability and aggressive motivation to the outcome of a contest? We found that aggression was triggered most frequently by female intrusions in the vicinity of nest and by extrapair female intrusions on an established pair. Female fighting and contest outcomes were strongly influenced by body condition and body size, and females were more motivated to initiate fights and won more contests when their mates were present. Females at the later breeding stages and those fighting closer to their nests were dominant and won more fights compared to females at earlier breeding stages or further from their nests. Females initiated a greater proportion of contests against opponents with similar local familiarity and breeding history. Escalated and prolonged contests, while rare, occurred exclusively between females of the most similar body size and condition. When differences in body condition between opponents are not easily perceived, contestants might escalate contests for more reliable assessments of relative fighting ability. Finally, body condition was not a strong determinant of contest outcome in the contexts with easily assessed differences in the resource value (e.g. mate presence), but without these motivational differences, body condition was the ultimate determinant of contest outcomes.

Abstract: This paper summarizes the current views on coping styles as a useful concept in understanding individual adaptive capacity and vulnerability to stress-related disease. Studies in feral populations indicate the existence of a proactive and a reactive coping style. These coping styles seem to play a role in the population ecology of the species. Despite domestication, genetic selection and inbreeding, the same coping styles can, to some extent, also be observed in laboratory and farm animals. Coping styles are characterized by consistent behavioral and neuroendocrine characteristics, some of which seem to be causally linked to each other. Evidence is accumulating that the two coping styles might explain a differential vulnerability to stress mediated disease due to the differential adaptive value of the two coping styles and the accompanying neuroendocrine differentiation.

Abstract: Lateralization of the brain appeared early in evolution and many of its features appear to have been retained, possibly even in humans. We now have a considerable amount of information on the different forms of lateralization in a number of species, and the commonalities of these are discussed, but there has been relatively little investigation of the advantages of being lateralized. This article reports new findings on the differences between lateralized and nonlateralized chicks. The lateralized chicks were exposed to light for 24 h on day 19 of incubation, a treatment known to lead to lateralization of a number of visually guided responses, and the nonlateralized chicks were incubated in the dark. When they were feeding, the lateralized chicks were found to detect a stimulus resembling a raptor with shorter latency than nonlateralized chicks. This difference was not a nonspecific effect caused by the light-exposed chicks being more distressed by the stimulus. Instead, it appears to be a genuine advantage conferred by having a lateralized brain. It is suggested that having a lateralized brain allows dual attention to the tasks of feeding (right eye and left hemisphere) and vigilance for predators (left eye and right hemisphere). Nonlateralized chicks appear to perform these dual tasks less efficiently than lateralized ones. Reference is made to other species in discussing these results.

Abstract: In group-living animals relative rank positions are often associated with differences in glucocorticoid output. During phases of social stability, when dominance positions are clear and unchallenged, subordinates often face higher costs in terms of social stress than dominant individuals. In this study we test this prediction and examine additional potential correlates of stress, such as reproductive season, age and amount of aggression received in wild, seasonally breeding Assamese macaques (Macaca assamensis). During a mating and a non-mating season we collected 394 h of focal observational data and 440 fecal samples of six adult and six large subadult males living in a multimale-multifemale group in their natural habitat in northeastern Thailand. The mating season was characterized by a general increase in aggressive behavior and glucocorticoid excretion across all males compared to the non-mating season. Among adult males, mating season glucocorticoid levels were significantly negatively related with dominance rank and positively with the amount of aggression received. Both relationships were non-significant among large subadult males. Thus, our results suggest that in adult Assamese macaques a high dominance position is not associated with high costs. Low costs of dominance might be induced by strong social bonds among top-ranking males, which exchange frequent affiliative interactions and serve as allies in coalitionary aggression against potentially rank-challenging subordinate males.

Abstract: In the process of domestication, dogs (Canis familiaris) and cats (Felis catus) have undergone thousands of years of genetic changes that have adapted them to the human environment. Both species have acquired a global distribution and it has become quite common to find homes with the two living side by side. Nevertheless, there is widespread belief that interspecific communication between dogs and cats is problematic, stemming from their separate evolutionary development and different social structures. Consequently, many people considering possible adoption of both species are concerned about their ability to get along. Interrelationships of dogs and cats living together were studied here in an attempt to determine the main factors influencing the type of relationship likely to develop between the two species. Two approaches were used: (1) a questionnaire completed by owners of both dog(s) and cat(s), which provided a broad database of the animals' behaviors; and (2) observations carried out in participants' homes on their dog-cat interactions. Two separate ethograms for dogs and cats served for analyses of their body language. The findings revealed the following: Both species showed a similar ability to establish a relatively amicable relationship with the other species; the animals' gender had little influence on the nature of their interrelationship; and adoption of the cat prior to the dog appears to conduce to establishing an amicable relationship, as does their first encounter taking place at an early age (up to 6 months of age in cats and up to 1 year in dogs). The findings also suggest that the majority of these dogs and cats understood the particular body language displayed by one animal that has an opposite meaning for the other species; and that the earlier the age of first encounter between the two, the better this understanding. It can be concluded that exposure of both species at an early age to the presence of the other facilitates the learning of each other's body language, and the consequent establishment of an amicable relationship. A better understanding of the various factors that contribute to determining the two species' relationship should not only improve the quality of life of these pets, but also reassure and encourage more people to adopt both cat and dog.