Abstract: The function of olfactory signalling in social species is less well understood than in asocial species. Consequently, we examined olfactory communication in the ringtailed lemur, a socially complex primate that retains a functional vomeronasal organ, has well-developed scent glands and shows a suite of scent-marking behaviour. To assess the information content of different types of scent gland secretions, we decoupled olfactory cues from the visual and behavioural modalities with which scent marking is normally associated. We presented male and female subjects (signal receivers) with a series of choice tests between odours derived from conspecific donors (signal senders) varying by sex, age, social status and reproductive condition. We additionally examined the influence of the receivers' reproductive state and familiarity with the signaller. The reproductive condition, social status and familiarity of senders and receivers affected signal transmission; specifically, male receivers attended most to the odours of conspecifics in breeding condition and to the odours of familiar, dominant animals. By contrast, females varied their responses according to both their own reproductive state and that of the sender. Based on male and female patterns of countermarking, we suggest that scent marking serves a function in intergroup spacing and intrasexual competition for both sexes, as might be expected in a female-dominant species. By contrast, minimal female interest in male odours counters a female mate choice function for scent marking in this species. Nevertheless, scent marks are critical to male-male competition and, therefore, may be subject to sexual selection.

Abstract: Achieving a high social rank may be advantageous for individuals at high population densities, because dominance status may determine the priority of access to limited resources and reduce individual loss of body mass. The establishment of dominance relationships between individuals involves variable levels of aggressiveness that can be influenced by resource availability. The relationship between social rank and aggressiveness and the impacts of resource abundance on aggressiveness are, however, poorly understood, but may be relevant to understand the mechanisms determining dominance relationships between individuals. We experimentally simulated, in seminatural enclosures, a deterioration of winter forage quality induced by a high-density deer population and examined the effects of (1) social dominance and (2) diet quality on aggressiveness, forage intake and body mass loss of white-tailed deer, Odocoileus virginianus, fawns during two winters. Within diet-quality treatments, fawns were consistently organized into linear hierarchies and showed clear dominance relationships. Dominants initiated more interactions and showed higher aggressiveness than subordinates, but subordinates had higher forage intake than dominants throughout winter. Social rank did not influence cumulative body mass loss of fawns. During both winters, fawns fed the control diet maintained their aggressiveness level, whereas fawns fed the poor-quality diet decreased it. Our experimental approach revealed that white-tailed deer responded to a reduction in winter forage quality by modifying their aggressiveness, indicating that ungulates may show plasticity not only in their foraging behaviour in response to decreased resources but also in their social behaviour.

Abstract: Our understanding of how, why, and the circumstances under which animals use social information has been facilitated by three principal areas of research, social learning, public information use and social eavesdropping. With few exceptions, these related concepts have remained remarkably distinct within the literature, with little discussion or integration among them. Are these distinctions warranted? We tackle the issue by exploring similarities and differences between the concepts with respect to how animals gather and use social information, the type of information gathered, how information is packaged, and the relative payoffs to individuals involved. We contend that none of the currently dominant paradigms, social learning, public information use, or social eavesdropping, provide a unifying theme for studying social information use. Instead, we favour the central characteristic of the three concepts, social information use, as the overarching umbrella, and advocate a broader conceptual framework for understanding more comprehensively how animals behave with their social environments. Our intention is not to revolutionize the fields of social learning, public information use or social eavesdropping, but rather to stimulate discussion among researchers investigating the abilities of animals to extract information from the social environment.

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: How animals use space has important consequences for feeding ecology, social organization, mating strategies and conservation management. In white rhinoceros, female home ranges are much larger than male territories, suggesting that movement patterns are influenced by factors other than resource distribution. In this study we placed radiotransmitters on 15 female white rhinoceros, recording 1758 locations and collecting behavioural data during 1671 observation sessions, making this the largest data set of its kind in this species. We investigated how habitat variables and male territories influenced female movement and reproductive behaviour. Female home ranges were approximately 20 km2 and core areas were 5 km2, with male territories roughly the same size as female core areas. Female range size did not vary with season, but the pattern of space use did vary. Females used grassland habitat preferentially, utilizing these areas significantly more than expected based on availability. Findings relevant to the mating strategy include: (1) the amount of grassland in a male's territory predicted female use of the territory; (2) the time that a female spent in a male's territory was a significant predictor of reproductive activity with the male, indicating that females probably mate with the most familiar male; and (3) the temporal pattern of female space use suggests that females did not increase mate sampling behaviour nor did they become more choosy about which males they visited when reproductively active. These findings suggest that males may maximize reproductive success by defending areas containing more grassland habitat.