Abstract: Animals that forage socially often stand to gain from coordination of their behaviour. Yet it is not known how group members reach a consensus on the timing of foraging bouts. Here we demonstrate a simple process by which this may occur. We develop a state-dependent, dynamic game model of foraging by a pair of animals, in which each individual chooses between resting or foraging during a series of consecutive periods, so as to maximize its own individual chances of survival. We find that, if there is an advantage to foraging together, the equilibrium behaviour of both individuals becomes highly synchronized. As a result of this synchronization, differences in the energetic reserves of the two players spontaneously develop, leading them to adopt different behavioural roles. The individual with lower reserves emerges as the 'pace-maker' who determines when the pair should forage, providing a straightforward resolution to the problem of group coordination. Moreover, the strategy that gives rise to this behaviour can be implemented by a simple 'rule of thumb' that requires no detailed knowledge of the state of other individuals.

Abstract: Observation of behaviour, especially social behaviour, and experimental studies of learning and brain function give us information about the complexity of concepts that animals have. In order to learn to obtain a resource or carry out an action, domestic animals may: relate stimuli such as human words to the reward, perform sequences of actions including navigation or detours, discriminate amongst other individuals, copy the actions of other individuals, distinguish between individuals who do or do not have information, or communicate so as to cause humans or other animals to carry out actions. Some parrots, that are accustomed to humans but not domesticated, can use words to have specific meanings. In some cases, stimuli, individuals or actions are remembered for days, weeks or years. Events likely to occur in the future may be predicted and changes over time taken into account. Scientific evidence for the needs of animals depends, in part, on studies assessing motivational strength whose methodology depends on the cognitive ability of the animals. Recognition and learning may be associated with changes in physiology, behaviour and positive or negative feelings. Learning and other complex behaviour can result in affect and affect can alter cognition. The demonstration of cognitive bias gives indications about affect and welfare but should be interpreted in the light of other information. All of the information mentioned so far helps to provide evidence about sentience and the level of awareness. The term sentience implies a range of abilities, not just the capacity to have some feelings. The reluctance of scientists to attribute complex abilities and feelings to non-humans has slowed the development of this area of science. Most people consider that they have obligations to some animals. However, they might protect animals because they consider that an animal has an intrinsic value, or because of their concern for its welfare. In social species, there has been selection promoting moral systems that might result in behaviours such as attempts to avoid harm to others, collaboration and other altruistic behaviour. An evaluation of such behaviour may provide one of the criteria for decisions about whether or not to protect animals of a particular species. Other criteria may be: whether or not the animal is known as an individual, similarity to humans, level of awareness, extent of feelings, being large, being rare, being useful or having aesthetic quality for humans. Cognitive ability should also be considered when designing methods of enriching the environments of captive animals.

Abstract: BACKGROUND: Foraging in groups offers animals a number of advantages, such as increasing their likelihood of finding food or detecting and avoiding predators. In order for a group to remain together, there has to be some degree of coordination of behaviour and movement between its members (which may in some cases be initiated by a decision-making leader, and in other cases may emerge as an underlying property of the group). For example, behavioural synchronisation is a phenomenon where animals within a group initiate and then continue to conduct identical behaviours, and has been characterised for a wide range of species. We examine how a pair of animals should behave using a state-dependent approach, and ask what conditions are likely to lead to behavioural synchronisation occurring, and whether one of the individuals is more likely to act as a leader. RESULTS: The model we describe considers how the energetic gain, metabolic requirements and predation risks faced by the individuals affect measures of their energetic state and behaviour (such as the degree of behavioural synchronisation seen within the pair, and the value to an individual of knowing the energetic state of its colleague). We explore how predictable changes in these measures are in response to changes in physiological requirements and predation risk. We also consider how these measures should change when the members of the pair are not identical in their metabolic requirements or their susceptibility to predation. We find that many of the changes seen in these measures are complex, especially when asymmetries exist between the members of the pair. CONCLUSION: Analyses are presented that demonstrate that, although these general patterns are robust, care needs to be taken when considering the effects of individual differences, as the relationship between individual differences and the resulting qualitative changes in behaviour may be complex. We discuss how these results are related to experimental observations, and how the model and its predictions could be extended.

Abstract: In many animal groups, certain individuals consistently appear at the forefront of coordinated movements [1-4]. How such leaders emerge is poorly understood [5, 6]. Here, we show that in pairs of sticklebacks, Gasterosteus aculeatus, leadership arises from individual differences in the way that fish respond to their partner's movements. Having first established that individuals differed in their propensity to leave cover in order to look for food, we randomly paired fish of varying boldness, and we used a Markov Chain model to infer the individual rules underlying their joint behavior. Both fish in a pair responded to each other's movements-each was more likely to leave cover if the other was already out and to return if the other had already returned. However, we found that bolder individuals displayed greater initiative and were less responsive to their partners, whereas shyer individuals displayed less initiative but followed their partners more faithfully; they also, as followers, elicited greater leadership tendencies in their bold partners. We conclude that leadership in this case is reinforced by positive social feedback.

Abstract: The relationship between social behaviour and skin injuries (caused by horns) of loose housed horned cows was investigated on 35 dairy farms. While the frequencies of two agonistic behaviour elements (push and chase away) were positively correlated with the occurrence of skin injuries, the frequencies of butting and homing were not. Butting appears to have an ambivalent motivation, in that its occurrence is correlated positively both with agonistic behaviour and with social licking. Horning showed a positive correlation with social licking only. Four groups of husbandry conditions that may be associated with the occurrence of social behaviour and of injuries were distinguished: i) herd management, with variables including problem solving management by the farmer, integration of new cows, and dealing with periparturient and oestrus cows; ii) human-animal relationship, with variables including ability to identify individual cows, frequency of brushing the cows, number of milkers, and frequency of personnel changes; iii) animal characteristics, with the variable of herd size; and iv) stable characteristics, with the variable of space per cow (m2). The relevance of the husbandry variables investigated here had been confirmed in a previous stepwise regression analysis (Menke 1996). The variables for herd management and human-animal relationship conditions correlated in a consistent way with the occurrence of agonistic behaviour and/or of injuries, while most of them also correlated in the opposite direction with the occurrence of social licking. Herd size correlated positively with agonistic behaviour, but negatively with social licking. Space per cow correlated negatively with agonistic behaviour and injuries. In more than 70 per cent of the herds investigated, the levels of agonistic behaviour and of skin injuries were low, implying that horned dairy cows can be kept with less risk than is often assumed. We argue that such risks strongly depend on management factors that can be improved.