Abstract: Observations of captive female brown capuchin monkeys in five groups revealed that grooming is primarily the occupation of dominant females at both the individual and dyadic levels. When categorized according to rank class, alpha females were the only class to perform significantly more grooming than they received. These results are inconsistent with reports on vervets, baboons and macaques, and suggest that grooming in capuchin monkeys may have different functions from those reported for cercopithecine primates. A dyadic analysis revealed, however, that grooming occurred more often between closely ranked females, similar to what is seen in several Old World monkey species. Therefore, some aspects of grooming in capuchins are similar to that seen in Old World monkeys, but the way they distribute grooming is different, which may prompt a re-evaluation of current theories regarding the social function of allogrooming in non-human primates.

Abstract: During the pre-maturation period crowded males of Schistocerca gregaria are more active than isolated ones but the greater part of their extra activity is not locomotory but consists of the kicking movements made in response to contact with other locusts. Isolated males walk less often during this period but tend to jump (or fly) more than crowded ones. Activity increases with maturity and the increase is greater in the isolated males so that in spite of the absence of mechanical stimulation by other locusts their locomotor activity is now at least as great as that of the crowded ones and their jumping activity greater. Within one batch there is a tendency for those males which are most active during the first two weeks of adult life to mature earliest. The activity of young males crowded with fledglings is at first similar to that of males crowded with older locusts, but after the first two weeks the activity of both mature and immature males is depressed by crowding with fledglings. Mature males habitually isolated become less active when temporarily crowded with fledglings, but not when crowded with mature males. Mature and immature males habitually crowded with fledglings become more active when temporarily isolated and still more active when crowded with each other, or with other mature males. The inhibiting effect of the fledglings on maturation and their depressive effect on activity should in natural conditions promote synchronization of maturation and the cohesion of the group. There was little difference in activity between young males kept in single pairs and in isolation, except that in one experiment the isolated ones jumped more often. Young males kept in pairs with mature males are more active during the first week of adult life than those kept in pairs with each other. The males paired with mature males were also seen feeding much less often than those paired with each other. This was the only treatment in which a significant effect on the frequency of feeding was recorded. The femoral vibrations made by both mature and immature males in response to stimulation by mature males, occur less often in habitually crowded males than in those temporarily crowded or kept with one mature male only. This is presumably the result of habituation to the stimulus. The behaviour of wild Schistocerca males in a large outdoor cage was very similar to that of a low density laboratory group. All results suggest that there is an association between high activity and rapid maturation. This is compatible with the conclusion from earlier work that a low level of feeding is associated with rapid maturation.

Abstract: According to the socioecological framework, transitivity (or linearity) in dominance relationships is related to competition over critical resources. When a population is structured into groups, the intensity of between- versus within-group competition influences the form and function of its social organization. Few studies have compared the type and relative intensity of competition at these two levels. African elephants have well-structured social relations, providing an exemplary system for such a study. We report on dominance hierarchies among free-ranging elephants and evaluate the factors that drive their socioecological structure to lie in a region of the three-dimensional nepotism/despotism/tolerance space rarely observed among social species; namely, where non-nepotistic, transitive dominance hierarchies within groups emerge despite kin-based philopatry and infrequent agonistic interactions over widely distributed resources. We found significant transitivity in dominance hierarchies between groups. Dominance relations among the matriarchs of different social groups were primarily age based, rather than driven by physical or group size, and group matriarch rank influenced the dominance relationships among nonmatriarchal females in the population. Our results suggest that between-group dominance relationships induce tolerance among group members, which in combination with high group relatedness, reduces the benefits of nepotism. We postulate that cognitive abilities and high risk of injury in contests enhance winner and loser effects, facilitating the formation of transitive dominance relationships, despite widely distributed resources over which infrequent competition occurs. The interplay of cognitive abilities, winner and loser effects, resource distribution, and within- and between-group dominance relationships may produce behaviour in other strongly social mammals that differs from that predicted by a superficial application of current socioecological models.

Abstract: Homo sapiensis increasingly being studied within the evolutionary (adaptationist, selectionist) framework favoured by animal behaviour researchers. There are various labels for such work, including evolutionary psychology, human behavioural ecology and human sociobiology. Collectively, we call these areas `human evolutionary psychology' (HEP) because their shared objective is an evolutionary understanding of human information processing and decision making. Sexual selection and sex differences have been especially prominent in recent HEP research, but many other topics have been addressed, including parent-offspring relations, reciprocity and exploitation, foraging strategies and spatial cognition. Many HEP researchers began their scientific careers in animal behaviour, and in many ways, HEP research is scarcely distinguishable from other animal behaviour research. Currently controversial issues in HEP, such as the explanation(s) for observed levels of heritable diversity, the kinds of data needed to test adaptationist hypotheses, and the characterization of a species-typical `environment of evolutionary adaptedness', are issues in animal behaviour as well. What gives HEP a distinct methodological flavour is that the research animal can talk, an ability that has both advantages and pitfalls for researchers. The proper use of self-reports and other verbal data in HEP might usefully become a subject of future research in its own right.

Abstract: Abstract. This paper examines the significance of imitation in non-human animals with respect to the phylogenetic origins of culture and cognitive complexity. It is argued that both imitation (learning about behaviour through nonspecific observation) and social learning (learning about the environment through conspecific observation) can mediate social transmission of information, and that neither is likely to play an important role in supporting behavioural traditions or culture. Current evidence suggests that imitation is unlikely to do this because it does not insulate information from modification through individual learning in the retention period between acquisition and re-transmission. Although insignificant in relation to culture, imitation apparently involves complex and little-understood cognitive operations. It is unique in requiring animals spontaneously to equate extrinsic visual input with proprioceptive and/or kinaesthetic feedback from their own actions, but not in requiring or implicating self-consciousness, representation, metarepresentation or a capacity for goal-directed action.