Abstract: In contrast to the great similarity in behaviour and ecology of the 6 extant Equid species, 2 distinct types of social organisation have evolved, and both are adapted to life in semi-arid to arid regions where environmental conditions force them to migrate seasonally or opportunistically.
The ranges of the various species overlap: Mountain Zebra Equus zebra and Plains Zebra E. quagga in South Africa and Namibia, Plains Zebra and Grevy's Zebra E. grevyi in Kenya and Ethiopia, Grevy's Zebra and African Wild Ass E. africanus in Ethiopia, Asiatic Wild Ass E. hemionus and Przewalski Horse E. przewalski in Mongolia and China. Although, in the overlap zones, individuals of the different species are using the same resources like water and grazing next to each other, they rarely make closer contacts.
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In the type 1 species, Horse, Plains Zebra and Mountain Zebra, the adults live in non-territorial, stable, one-male families and as single bachelors and in bachelor groups. Family stallions have the exclusive mating rights with the mares in their harems. These consist of up to 6 unrelated mares plus their offspring, totalling up to 20 members.
Mares stay in their harem until death. Stallions' tenure is from age 5-6 years, i.e. when they succeed in controlling a harem, for close to life time, but are replaced when dead or incapacitated. Harems are stable even in the absence of a stallion, indicating voluntary membership. Adolescent mares leave their parental families to become members of another harem.
In Plains Zebra the adolescent mares are abducted, during an oestrus, by suitors who fight the defending family stallion/father. Successful stallions are bachelors who start a family, or family stallions enlarging their harem. Young stallions leave their parental families voluntarily at age 2-3 years and join bachelor stallion groups from where the family stallions are recruited.
An individualised dominance hierarchy excists with the stallion in the alpha position. It is based on individual knowledge and recognition of the members.
In the type 2 species Grevy's Zebra, African Wild Ass and Asiatic Wild Ass adult stallions monopolise territories in which they have the exclusive mating rights. Stallions are tolerant of any conspecifics entering their territory. Bachelor stallions behave subordinately – or fight for the possession of the territory which is a prerequisite for reproduction.
Mares join up to form anonymous and unstable groups or herds. The only stable unit is of a mare and her offspring. In Grevy's Zebra mares with foal join preferentially conspecifics of the same soial status, as do mares without foal.
Matings take place inside the territory. There is no lasting relationship of the mare with a particular stallion, and the mare may be mated by any stallion whose territory she is visiting.
Territories measure up to 10 or more square kilometres, and tenure is for several years.
Grevy Zebra territorial owners leave their territories for a few hours to visit a water hole, or for months when grazing and water conditions are below requirements, and re-occupy it upon return, unchallenged.

Abstract: To investigate the functions of social licking in cattle, four calves (one heifer and one steer in each of two herds), known to exhibit frequent social licking were observed continuously for 2 h before sunset for 13 days, using the focal animal sampling method. Calves were observed under various environmental conditions. Social licking significantly decreased on rainy days and tended to increase in a dirty barn and when food was restricted. Solicitation for social licking occurred not only from dominant animals of pairs but also from subordinates. Of the licking interactions, 31% occurred following solicitation, and these accounted for 39% of the total time spent licking. Following solicitation, 78% of social licking was oriented to the head and the neck regions that were inaccessible to self-licking animals. Unsolicited licking, however, was oriented not only to the head and the neck but also to the back and the rump regions, and these two latter regions were the major ones to receive licking. The effect of social relationships on social licking was investigated using least-squares analysis of variance. Social factors investigated were the difference of dominance values, the dominance-subordinance relationship, and kinship and familiarity; the sex of calves involved was also considered. Only familiarity had a significant effect on licking; exchanges of social licking increased with length of cohabitation. We suggest that social licking may have a cleaning effect, a tension-reducing effect and a bonding effect.

Abstract: Using heart rate (HR) measurements we investigated whether potential calming effects of social licking were evident for both active (performers) and passive (receivers) licking partners. A HR decline was assumed to indicate relaxation and thus the experience of positive emotions. Effects of the licking category (spontaneous, solicited), the animals' basic activity (standing, lying) and the licked body region (head, neck, rest) were also considered. Two studies (A, B) were carried out in the same loose housed Austrian Simmental dairy herd. HR was recorded in up to 20 focal animals on 16 and 18 days, respectively. Using either direct observations (A) or video recordings (B), social licking interactions were continuously observed. The cow's basic activity was recorded using scan sampling at 5 min intervals. Linear mixed effects models were applied separately for Study A and B in order to compare the mean HR of the licking bouts with the mean of the respective 5 min pre- and post-licking periods. In receivers we found a significant calming effect in terms of a HR decline during allogrooming in both studies (A: -1.3 beats per minute, B: -1.1 bpm). This effect was more pronounced when animals were standing (A/B: -2.4 bpm/-3.8 bpm). However, it was not affected by the licked body region. In dairy cows performing social licking, we did not find an overall calming effect. On the contrary, in Study B, HR significantly increased during licking in lying performers (+2.5 bpm). This reaction was even stronger, when licking was directed to the receivers' head (+3.5 bpm) or neck (+3.0 bpm) as compared to the rest of the body (+1.4 bpm). The licking category had no effect on HR changes during the licking events. Our findings suggest that relaxation effects induced by social licking differ between performers and receivers and are affected by the cows' basic activity. In receivers, there were clear indications of a calming effect implying the experience of positive affective states. In performers, such calming effects during social licking were not identified.

Abstract: Learning through the observation of others allows the transfer of information without the costs incurred during individual trial and error learning. Horses (Equus caballus) are a highly social species, which might be expected to be capable of learning from others, but experimental findings are inconsistent, and potentially confounded by social facilitation effects not related directly to the learning of the task. We refined the methods used in previous equine social learning studies, to examine and distinguish specific social influences on learning of a task: we used predefined group leaders rather than agonistically dominant individuals to demonstrate a detour task to familiar conspecific observers; in addition we had two control groups: a non-observer (true control) and a group with the demonstrator simply present at the goal (social facilitation control). 44 socially kept horses were allocated to one of the three test conditions and took part in five trials each. Success rate, latency and detour direction were recorded. There was no significant difference between the three groups in the likelihood of them succeeding in the task nor latency to succeed; however there was a significant difference in the route chosen by the groups, with the true control choosing the side with the entrance gate significantly more than either the observer group or social facilitation group. Both of the latter two groups chose to go in the same direction relative to themselves, regardless of which side the gate was. Seven out of nine horses in the observer group chose the same direction as their demonstrator every time. Our results show a significant role of social facilitation on detour behaviour and highlight the importance of including adequate controls for simpler cognitive influences on behaviour before claims can be made about the specific learning of motor actions or goal directed behaviour. Social cues may be important to horses if the task is sufficiently challenging and motivationally important, so future work should consider more demanding, but ecologically relevant situations, in order to maximise the potential revelation of social learning effects which do not depend on simple local or stimulus enhancement effects.

Abstract: Prima facie, the acquisition of novel behaviors in animals through observation of conspecifics seems straightforward. There are, however, various mechanisms through which the behavior of animals can be altered from observing others. These mechanisms range from simple hard-wired contagious processes to genuine learning by observation, which differ fundamentally in cognitive complexity. They range from social facilitation and local enhancement to true social learning. The different learning mechanisms are the subject of this review, largely because research on learning by observation can be confounded by difficulties in interpretation owing to the looming possibility of associative learning infecting experimental results. While it is often assumed that horses are capable of acquiring new behavior through intra-species observation, research on social learning in horses includes a variety of studies some of which may overestimate the possession of higher mental abilities. Assuming such abilities in their absence can have welfare implications, e.g. isolating stereotypical horses on the assumption that these behaviors can be learned though observation by neighboring horses. This review summarizes the definitions and criteria for the various types of social transmission and social learning and reviews the current documentation for each type in horses with the aim of clarifying whether horses possess the ability to learn through true social learning. As social ungulates, horses evolved in open landscapes, exposed to predators and grazing most of the day. Being in close proximity to conspecifics may theoretically offer an opportunity to learn socially, however anti-predator vigilance and locating forage may not require the neural complexity of social learning. Given the significant energetic expense of brain tissue, it is likely that social facilitation and local enhancement may have been sufficient in the adaptation of equids to their niche. As a consequence, social learning abilities may be maladaptive in horses. Collectively, the review proposes a novel differentiation between social transmission (social facilitation, local and stimulus enhancement) and social learning (goal emulation, imitation). Horses are undoubtedly sensitive to intra-species transfer of information but this transfer does not appear to satisfy the criteria for social learning, and thus there is no solid evidence for true social learning in horses.