Abstract: Summary Animals have several types of magnetic organ, often separately specialized for determining direction versus location. Recent results offer hints about how these once-unimaginable detectors may have evolved.

Abstract: We observed a high-density herd (200 mares/ha) of 44 Arab breeding mares, while in a bare paddock in Tunisia. Twenty-minute animal focal samples and scan sampling were used to determine the time budget of the mares during the period from 9 a.m. to 3 p.m. and study their social behaviour. The data obtained reveal restricted behavioural repertoires with missing behaviour like rolling, allogrooming and lying down; unusual time budgets with a high frequency of locomotion that constitutes the most frequent activity (27.9 ± 19.47%) of the mares. Social interactions were restricted to agonistic interactions but despite the high stocking density, aggressions were not that frequent among mares.

Abstract: The colours of the horses have long been a subject of interest to owners and breeders of horses as well as to scientists. Though, the colour of horses has little to do with its performance, it is a primary means of identification and also the first indicator of questionable parentage. Probably the ancestral colour of the horse was a black-based pattern that provided camouflage protection against predators. Horse colours are mostly controlled by genes at 12 different loci. The three basic colours of horses are black, bay and chestnut. The genetic control of the basic colours of horses resides at two genetic loci, namely Extension (E) and Agouti (A) loci. Among the basic colours bay is dominant to black and both are epistatic to chestnut. Dilution of basic colours of horses as a result of four colour dilution genes such as cream dilution, dun, silver dapple and champagne resulted in extensive array of possible colours of horses. The most widespread and familiar of the horse colour dilution gene is the one that produces the golden body colour and are called as palomino or buckskin based on the colour of the points. The grey coat colour is due to the presence of dominant gene (G) at the grey locus. Grey is epistatic to all coat colour genes except white and a grey horse must have at least one grey parent. Roan is due to a dominant gene (Rn) at roan locus and this combines with any base colour to produce the various shades of roan pattern. White coat is due to a single dominant gene (W) and it is epistatic to the genes controlling all other colours. White marking in the face and legs are due to genetic and non-genetic factors. Several genes are involved in producing white markings. During recent years, comparative genomics and whole genome scanning have been used to develop DNA tests for different variety of horse colours. Molecular genetic studies on coat colour in horses helped in identification of the genes and mutation responsible for coat colour variants. In future, this will be applied to breeding programmes to reduce the incidence of diseases and to increase the efficiency of race horse population.

Abstract: Temperament is an important factor when working with horses. Behavioural tests have already been developed to measure certain dimensions of a horse's temperament (fearfulness, gregariousness, etc.). In order to measure the temperament more precisely, our work aimed to identify a dimension which has already been described in several species but not yet in horses, namely sensory sensitivity. Our study was based on the definition of a temperament dimension as “a behavioural characteristic stable across situations and over time”. We designed several tests for each sense and then determined whether the responses observed were correlated between situations and in time. The principle of the tests was to generate two stimuli of different intensities for each sense (e.g. two different sounds) and to measure the intensity of the horse's response (N = 26). Using Spearman rank correlations, we tested whether the responses to these different stimuli were inter-correlated. We repeated the same tests 5 months later to determine whether the responses were correlated over time. Within each sense, results show that the greater the horses' response to one stimulus, the greater their response to the other. For example, the reaction to the odour of cinnamon (time spent near the source of the odour) was significantly correlated to the reaction to lavender (R = 0.53, p = 0.004). The reactions to two different sounds or to two different tactile stimuli (von Frey filaments, or contact of a brush on the body), were also significantly correlated (R = 0.59, p < 0.0001; R = 0.38, p = 0.029). Finally, the reactions to two different tastes or to two visual stimuli tended to be correlated (R = 0.27, p = 0.09; R = 0.27, p = 0.09). However, there was no significant correlation between the responses to stimuli relating to different senses. Finally, except for the responses to odour, the responses to other sensory stimuli showed stability over a 5-month period (e.g. tactile stimulation: R = 0.71, p < 0.0001). In conclusion, our study revealed characteristics which were stable across situations and over time. The absence of links between the characteristics measured for the different senses suggests that a dimension for each sense exists (e.g. tactile sensitivity) rather than a general sensory sensitivity dimension covering all the senses.

Abstract: Previous research on the allocation of scarce resources shows that when people are assigned labels of leader or follower in their group, leaders allocate more of the scarce resources to themselves than followers do. In three laboratory studies, we examine the idea that how people are selected for the leader role (i.e. election or appointment) determines whether leaders take more or equal shares (relative to followers) from a common resource. In a first experiment, we show that participants were more accepting of norm violating behavior by an appointed versus elected leader. In a second experiment, we show that when participants were assigned to a leader or follower role, allocations of appointed leaders differed significantly from those of elected leaders and followers, whereas there was no difference between the two latter conditions. Moreover, elected leaders were shown to feel more social responsibility than both appointed leaders and followers. In a final experiment, we show that when participants were primed with the concept of social responsibility (relative to a neutral condition) no difference in allocations between appointed and elected leaders emerged.