Abstract: Abstract. Fifteen years of data on natal dispersal age and the context of dispersal for the feral ponies of Assateague Island, Maryland are presented. Ninety-seven per cent of males and 81% of females dispersed from their natal groups by 5 years of age. For animals that left their natal group, average age of dispersal was 20[middle dot]8 months for males and 24[middle dot]6 months for females. Male dispersal age was strongly and significantly correlated with number of peers in the natal group, and males dispersing with peers were significantly older than males dispersing without peers, suggesting that males delayed dispersal when peers were available for interaction. Female dispersal age was not influenced by number of peers, but was correlated with age of first reproduction. Factors not influencing dispersal age in either sex were presence of a younger sibling, maternal band transfers, and maternal age and dominance rank. The relatively high frequency of females failing to disperse from their natal groups is puzzling in light of data showing diminished fecundity in non-dispersing pony mares.

Abstract: Differences in behavioural characteristics between individuals of the same species are often described as being due to the temperament of the individuals. These differences can have enormous implications for welfare with some individuals apparently being able to adapt to environmental challenge more easily than others. Such differences have resulted in animals often being described as either `active' copers, which try to escape from or remove an aversive stimulus, or `passive' copers, which show no outward signs of a situation being aversive, thus, appearing to be unaffected. Tests previously developed to assess the temperament of animals have been criticised for several reasons. Behaviour is often recorded and categorised using methods that are not objective and tests are generally carried out once with no consideration of whether or not behavioural responses are consistent over time. This study takes these factors into account. The behaviour of 33 horses was recorded in three types of test--an arena test, response to a person and response to an object. In order to test whether or not responses were consistent over time, the tests were repeated three times with an average of 9 days between trials. Test results were validated using responses from questionnaires completed by the farm team leader. The data were analysed using an initial principal component analysis (PCA) and factor analysis. The horses were found to behave consistently over the three trials in their responses in the arena test. The responses to the person test and the object test were similar to each other; however, these responses were not consistent over trials. The behaviour in the arena test was unable to be used to make a prediction of behaviour in the person and object tests and vice versa. The responses shown by the horses did not enable them to be categorised as either active or passive copers. Behavioural responses in the tests were not predictive of the response to a startle test (water spray), nor could they be used to predict status or response to being reintroduced to the group after testing. There was no relationship between the responses in the tests and the ratings given by the farm team leader. It was concluded that horses vary widely in their responses to artificial behavioural tests, with only the responses to an open-field arena test being consistent over time, and therefore, the only type of test which can indicate some core factor of temperament.

Abstract: When detecting a predator, some prey animals respond in a counterintuitive fashion by approaching, rather than fleeing, that potential threat of extinction. This seemingly paradoxical behaviour, known aspredator inspection, has been reported for a wide variety of taxa--and therefore can be assumed to be adaptive. However, the view of predator inspection as a paradoxical behaviour rests on two implicit assumptions: (a) initial predator detecting is unambiguous, with no uncertainty in discriminating between hunting and non hunting members of predator species, or members of predator species and unrelated phenomena; (b) the costs of flight are negligible relative to the risk of predation. Upon reflection assumption (a) is not really tenable. Whereas assumption (b) is not consistent with experimental evidence [Godin & Crossman (1994)Behav. Ecol. Sociobiol.34,359-366]. Given that predator detection is ambiguous and the costs of flight are not negligible, a prey individual may benefit by a closer approach to the source of the alarming signals, thus improving its assessment of the situation--despite the increased risk of predation. In this paper, the above statement is given rigor by reformulating the problem in game theoretical terms. The results indicate that a prey will minimize its costs by performing predator inspection whenever its degree of certainty regarding predator identification and/or assessment of its intentions is less than a threshold, which is determined by the model's parameters.

Abstract: Idiosyncratic motor behaviour was investigated during four experimental procedures in 40 horses (males = 20, females = 20) to establish if horses revealed evidence of significant right or left laterality. The experimental procedures included (1) detection of the preferred foreleg to initiate movement (walk or trot), (2) obstacle avoidance within a passageway (right or left), (3) obstacle avoidance when ridden and (4) idiosyncratic motor bias when rolling. The influence of the horses' sex on both the direction and the degree of the laterality was explored within and between experimental procedures. The findings showed that the direction, but not the degree of idiosyncratic motor preference in the horses was strongly sex-related. Male horses exhibited significantly more (t = 3.74, d.f. = 79, P < 0.001) left lateralised responses and female horses exhibited significantly more (t = -6.35, d.f. = 79, P < 0.01) right lateralised responses. There was also significant positive correlation (P < 0.05) between four of six possible inter-experimental relationships. The results suggest two discrete trends of laterality associated with the sex of the horse. The primary cause of idiosyncratic motor laterality may be genetically predetermined, influenced by environmental factors or a combination of these two and the current findings may support the development of sex-specific training schedules for the horse. Further, work in this area might assist in defining the mechanisms of brain hemisphere lateralisation and allocation of cognitive function in the horse.