Abstract: Both white-tailed deer, Odocoileus virginianus, and mule deer, O. hemionus, females defend fawns against coyotes, Canis latrans, but only mule deer defend nonoffspring conspecific and heterospecific fawns. During a predator attack, females may have to decide whether to defend a fawn while having imperfect information on its identity obtained from hearing a few distress calls. Although imperfect recognition can influence altruistic behaviour, few empirical studies have considered this point when testing functional explanations for altruism. We designed a series of playback experiments with fawn distress calls to test alternative hypotheses (by-product of parental care, kin selection, reciprocal altruism) for the mule deer's defence of nonoffspring, specifically allowing for the possibility that females mistake these fawns for their own. White-tailed deer females approached the speaker only when distress calls of white-tailed deer fawns were played and when their own fawn was hidden, suggesting that fawn defence was strictly a matter of parental care in this species. In contrast, mule deer females responded similarly and strongly, regardless of the caller's identity, the female's reproductive state (mother or nonmother) or the presence of their own offspring. The failure of mule deer females to adjust their responses to these conditions suggests that they do not defend nonoffspring because they mistake them for their own fawns. The lack of behavioural discrimination also suggests that kin selection, reciprocal altruism and defence of the offspring's area are unlikely to explain the mule deer's defence of nonoffspring. We identify causal and functional questions that still need to be addressed to understand why mule deer defend fawns so indiscriminately.

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: Mirror usage has been taken to indicate some degree of awareness in animals. Can pigs, Sus scrofa, obtain information from a mirror? When put in a pen with a mirror in it, young pigs made movements while apparently looking at their image. After 5 h spent with a mirror, the pigs were shown a familiar food bowl, visible in the mirror but hidden behind a solid barrier. Seven out of eight pigs found the food bowl in a mean of 23 s by going away from the mirror and around the barrier. Naïve pigs shown the same looked behind the mirror. The pigs were not locating the food bowl by odour, did not have a preference for the area where the food bowl was and did not go to that area when the food bowl was visible elsewhere. To use information from a mirror and find a food bowl, each pig must have observed features of its surroundings, remembered these and its own actions, deduced relationships among observed and remembered features and acted accordingly. This ability indicates assessment awareness in pigs. The results may have some effects on the design of housing conditions for pigs and may lead to better pig welfare.

Abstract: It has been suggested that social dynamics affect social learning but empirical support for this idea is scarce. Here we show that affiliate relationships among kin indeed enhance the performance of common ravens, Corvus corax, in a social learning task. Via daily behavioural protocols we first monitored social dynamics in our group of captive young ravens. Siblings spent significantly more time in close proximity to each other than did nonsiblings. We subsequently tested birds on a stimulus enhancement task in model-observer dyads composed of both siblings and nonsiblings. During demonstration the observer could watch the model manipulating one particular object (target object) in an adjacent room. After removing the model, the observer was confronted with five different objects including the former target object. Observers from sibling dyads handled the target object for significantly longer periods of time as compared with the other four available objects, whereas observers from nonsibling dyads did not show a preference for the target object. Also, siblings matched the model's decision to cache or not to cache objects significantly more often than did nonsiblings. Hence, siblings were likely to attend to both, the behaviour of the model (caching or noncaching) and object-specific details. Our results support the hypothesis that affiliate relations between individuals affect the transmission of information and may lead to directed social learning even when spatial proximity has been experimentally controlled for.

Abstract: Benjamin Beck's definition of tool use has served the field of animal cognition well for over 25 years (Beck 1980, Animal Tool Behavior: the Use and Manufacture of Tools, New York, Garland STPM). This article proposes a new, more explanatory definition that accounts for tool use in terms of two complementary subcategories of behaviours: behaviours aimed at altering a target object by mechanical means and behaviours that mediate the flow of information between the tool user and the environment or other organisms in the environment. The conceptual foundation and implications of the new definition are contrasted with those of existing definitions, particularly Beck's. The new definition is informally evaluated with respect to a set of scenarios that highlights differences from Beck's definition as well as those of others in the literature.