Abstract: Feral asses have been studied in the arid habitats of the southwestern United States [Moehlman, P.D., 1974. Behavior and ecology of feral asses (Equus asinus). PhD dissertation, University of Wisconsin, Madison, 251 pp.; Moehlman, P.D., 1979. Behavior and ecology of feral asses (Equus asinus). Nat. Geogr. Soc. Res. Reports 1970, 405-411.; Woodward, S.L., 1979. The social system of feral asses (Equus asinus). Z. Tierpsychol. 49, 304-316] and in the mesic habitat of Ossabaw Island, Georgia [Moehlman, P.D., 1979, ibid; McCort, W.D., 1980. The feral asses (Equus asinus) of Ossabaw Island, Georgia. PhD dissertation, Pennsylvania State University, University Park, 219 pp]. The feral ass populations in these two locales exhibited intraspecific variation in polygynous mating systems and social organization which were consistent with the ecological classification of mating systems of Emlen and Oring (1977) [Emlen, S.T., Oring, S.W., 1977. Ecology, sexual selection, and the evolution of mating systems. Science 197 (4300), 215-223]. Feral asses in the arid environment have a `resource defense' polygynous mating system, and those in the mesic habitat exhibit `female (harem) defense' polygyny. The intraspecific variation observed in feral asses encompasses the interspecific variation observed in the family Equidae.

Abstract: Play behaviour is widespread in mammals, but benefits to play have been difficult to demonstrate. Physical training is one of the many proposed hypotheses, suggesting that males and females should play differently, that increased maternal investment should lead to increases in play, and that increases in play should result in physical advantages. In a population of feral horses, Equus caballus, males and females did not differ in their play behaviour except that males initiated more of their play bouts than females. Maternal condition influenced play behaviour only in males, with sons of mothers in good condition playing more. However, when we controlled for maternal effects by comparing a son and a daughter of the same mother, daughters played more when their mother was in poor condition and sons played more when their mother was in good condition. Mothers of foals that played more lost more condition. Therefore, the difference in play behaviour could not be explained by offspring sex or maternal condition alone, but play behaviour mirrored variation in maternal investment. In addition, those individuals that played more survived better and had better body condition as yearlings despite weaning earlier. Since increased activity has been linked to enhanced musculoskeletal development in domestic horses, we suggest that play provides a link between increased maternal investment, increased body condition and future reproductive success in feral horses, and probably in other species.

Abstract: Horses maintain the social structure through the establishment of dominant-subordinate hierarchical relationships, both within and between groups. The object of study was the feral horse population, living on the Vodnyi Isl, Manych-Ghudilo Lake, on the territory of Rostov Region, S Russia the State Nature Biosphere Reserve “Rostov”. The social structure of this population is represented by the harem and bachelor groups, and their variety – the “mixed”groups, the presence and composition of which is atypical for the populations of feral horses. The main objectives of this work were to identify the hierarchical structure of different types of social groups and the role of the stallions in them, defining the dominance rank of animals. The method of continuous logging occurred aggressive reaction, ritualized interaction between stallions, take into account the direction of interactions between individuals. We observed 5 harem, 3 bachelor and 3 mixed groups. Each group was studied for a total of 60 h (8 h per group per days).Behavioral observations were carried out in summer 2009-2011. Based on the number and direction of aggressive interactions the hierarchical coefficient was calculated for individual horses (Ivanov et al, 2007). Harem group consists of an adult stallion (<5 years old) and a few mares with their offspring. Our observations of harem groups confirm the previously known information about this type of social groups (Berger, 1986; Carson, Wood-Gush, 1983, Keiper, 1983). Hierarchical system between mares is close to linear with reversal. The stallion is not included in the hierarchy of the mares; he is the leader and serves to maintain the integrity of the group and inter-group hierarchy, and has reproductive function. Bachelor groups consist of stallions 2-3 years and older who do not have their own harem. It is known that dominance hierarchy in these groups is linear, young males or males who recently had joined the group have low ranks (Berger, 1977; Houpt, Keiper, 1982; Kirillov Paklina, 1990). In observed bachelor groups dominant stallion have a significantly higher rank in the hierarchy. However, among other stallions is not always observed strict linear hierarchy – some individuals have very similar ranks. Function of managing the group and maintaining the intergroup hierarchy can be distributed among the all stallions in the group. Mixed groups are composed of several mature stallions, one or more mares (sometimes with the offspring). In the study population in this type of social groups animals may be mature (age 5 and older) and semi-mature (2-5 years). The hierarchy of these atypical groups has not been studied. In the studied 3 mixed groups stallions have very similar hierarchical rank, dominant and subordinate stallions share a function of managing the group, participation in ritualized interactions. Our studies have revealed the plasticity of the hierarchical structure of groups of horses and the need to further investigate the distribution of social roles among stallions.

Abstract: Observational field studies were conducted on two remote populations of feral horses in Australia to determine whether lateralization is a characteristic of Equus caballus as a species or results from handling by humans. Group 1 had been feral for two to five generations and Group 2 for 10–20 generations. In both groups, left-side biases were present during agonistic interactions and in reactivity and vigilance. Therefore, as in other vertebrates, the right hemisphere appears to be specialized to control agonistic behaviour and responses to potential threats. The leftwards bias was stronger in measures of behaviour involving more aggression and reactivity. Preferences to place one forelimb in front of the other during grazing were also determined. No population bias of forelimb preference was found, suggesting that such limb preferences present in domestic horses may be entrained. Since stronger individual limb preferences were found in immature than in adult feral horses, limb preference may be modified by maturation or experience in the natural habitat. Stronger limb preference was associated significantly with elevated attention to the environment but only in younger feral horses. No sex differences in lateralization were found. The findings are evidence that horses show visual lateralization, as in other vertebrates, not dependent on handling by humans. Limb preference during grazing, by contrast, does appear to depend on experience.

Abstract: Objective  The aims of this work were to (1) develop a low-cost equine movement tracking collar based on readily available components, (2) conduct preliminary studies assessing the effects of both paddock size and internal fence design on the movements of domestic horses, with and without foals at foot, and (3) describe distances moved by mares and their foals. Additional monitoring of free-ranging feral horses was conducted to allow preliminary comparisons with the movement of confined domestic horses. Procedures  A lightweight global positioning system (GPS) data logger modified from a personal/vehicle tracker and mounted on a collar was used to monitor the movement of domestic horses in a range of paddock sizes and internal fence designs for 6.5-day periods. Results  In the paddocks used (0.8-16 ha), groups of domestic horses exhibited a logarithmic response in mean daily distance travelled as a function of increasing paddock size, tending asymptotically towards approximately 7.5 km/day. The distance moved by newborn foals was similar to their dams, with total distance travelled also dependent on paddock size. Without altering available paddock area, paddock design, with the exception of a spiral design, did not significantly affect mean daily distance travelled. Feral horses (17.9 km/day) travelled substantially greater mean daily distances than domestic horses (7.2 km/day in 16-ha paddock), even when allowing for larger paddock size. Conclusions  Horses kept in stables or small yards and paddocks are quite sedentary in comparison with their feral relatives. For a given paddock area, most designs did not significantly affect mean daily distance travelled.