Abstract: previous termSocial cognition,next term in particular the derivation of previous termsocialnext term information from observation of interactions between members of a previous termsocialnext term group, has been widely investigated in primates, but it has received little attention in other previous termsocialnext term mammals, although it has been anecdotally reported in the previous termdomestic dog,next term Canis familiaris. We recorded the behaviour of previous termdogsnext term (“spectators”) that had observed controlled interactions between a human and a previous termdognext term (the “demonstrator”) competing for an object, and that were subsequently allowed to interact freely with both participants. When the competitions were playful, as indicated by signals performed by the human, the spectator was more likely to approach the winner first and/or more rapidly, suggesting that winners of games are perceived as desirable previous termsocialnext term partners. When the human did not perform play signals, changing the previous termsocialnext term context from play to contest over a resource, spectators were slower to approach either of the participants, suggesting that participants in contests were less desirable as previous termsocialnext term partners than participants in games. If the previous termdognext term was prevented from seeing the game, it still reacted differently to the winner and the loser, but its behaviour was not the same as after games that it had seen. We conclude that spectator previous termdogsnext term gain information from the players' subsequent behaviour as well as from direct observation of the game.

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: Gestures and facial displays are involved in regulating many aspects of mammal social life such as aggression, dominance-subordinate relationships, appeasement and play. Playful activity is an interesting behaviour for examining the role of signals as intentional communication systems. When animals play they perform patterns that are used in other serious contexts. To avoid miscommunication, many species have evolved signals to maintain a playful mood. Bonobos, Pan paniscus, with their flexible social relationships and playful propensity, may represent a good model species to test some hypotheses on adult play signalling. I analysed the potential roles of facial play expressions and solitary play in soliciting and regulating social play and found that adult bonobos used the play face (relaxed open-mouth display) in a selective manner. Play faces were more frequent during social than solitary play and, within social play, polyadic sessions (even though less frequent than dyadic sessions) were characterized by a higher frequency of signals. Following the rule of play intensity matching, play faces were more frequent when the two players matched in age and size (sessions among adults). Moreover, among dyads there was a positive correlation between the frequency of aggressive interactions performed and the frequency of play signals used, thus suggesting that signals are crucial in play negotiations among individuals showing high baseline levels of aggression. Finally, solitary play, especially when it involved pirouettes and somersaults, had an important role in triggering social play.

Abstract: Lactating female baboons, Papio cynocephalusoften maintain close associations with particular males. There are at least three proposed benefits of 'friendships' to females: (1) male protection against potentially infanticidal males; (2) male protection against harassment by dominant females; (3) male attachment to an infant that develops into future care of juveniles. These hypotheses were examined in a population of chacma baboons, P. c. ursinusin which male infanticide accounted for at least 38% of infant mortality. Almost all mothers of young infants formed strong bonds with one or two males with whom they had copulated during the cycle in which they conceived their infants. Females were primarily responsible for maintaining friendships during lactation, but they terminated these relationships if their infants died. In playbacks of females' screams, male friends responded more strongly than control males. They also responded more strongly to the screams of female friends than to the screams of control females. Following an infant's death, however, male friends responded less strongly than control males to the same females' screams. Finally, male friends responded more strongly than control males to playback sequences in which female screams were combined with the threat vocalizations of a potentially infanticidal alpha male, but not when female screams were combined with the threat calls of a non-infanticidal male or the alpha female. Both observations and experiments suggest that the benefits of friendships to females derive from the protection of their infants against infanticide.1997The Association for the Study of Animal Behaviour

Abstract: It was formerly argued that alternative evolutionarily stable strategies (ESSs) are possible for animal contests characterized by some asymmetry that can be perceived with perfect accuracy. Where roles A and B refer to the asymmetry between opponents, ESSs are: [`]fight when A, retreat when B', and vice versa. Either can be an ESS, but only if the [`]reserve strategy' (=what an animal does when it fights) is sufficiently damaging. We examine the [`]war of attrition' (winner = opponent that persists longer). In a population at either ESS, reserve strategy is never normally shown; it is therefore subject to drift unless the selective action of rare individuals which break the convention is considered. These could arise either by mutation or by mistakes in role assessment. When mutations and mistakes simply specify that occasionally an animal fights when it [`]should' retreat, selection adjusts reserve strategy to a level where only one ESS (the [`]commonsense' ESS) is possible, if the asymmetry is relevant to payoff. Thus for asymmetries in fighting ability or resource value, the individual with the lower score will retreat. However, we are particularly concerned with cases where both payoff-relevant aspects (fighting ability and resource value) are asymmetric. If opponents sustain contest costs at rates KA and KB, and their resource values are VA and VB, an [`]optimal assessor' strategy defined by the interaction between the two asymmetries, is a unique ESS. It obeys the rule [`]fight on estimating role A, where VA/KA>VB/KB; retreat in B'. If mistakes can occur in both roles, but are very rate, the ESS is not fundamentally altered though there will be infinitesimal tendencies for persisting in role B. Selection to improve assessment abilities intensifies as abilities improve, but is weak if roles A and B are rather similar. Over a range of similarity between roles, an [`]owner wins' convention may be adopted if ownership correlates positively with role A and an individual cannot tell when it would otherwise pay him to break the convention. We also examine a contest in which information about roles can be acquired only during a contest itself, and at a cost. Much depends on the rate at which information is acquired relative to the rate at which costs are expended, and on whether contests normally escalate in intensity, remain at the same level, or de-escalate. Selection favours short contests when costs are high relative to resource value, where the outcome of a round contains much information about fighting ability, and where the actual disparity in fighting ability is large.