Abstract: In the social organization of feral horses, adult males compete to monopolize groups or bands of females, sometimes called harems. Alternative male strategies are to remain alone or with other bachelors or, less commonly, to accept subordinate status within a harem. The hypothesis that dominant harem stallion status confers a reproductive advantage was tested in free-ranging feral horses. The presence of foals in harems headed by vasectomized (VSX) versus intact stallions was used to assess the ability of these stallions to control reproduction in their harems. Of harems headed by VSX stallions, 17 and 33% contained foals during years 2 and 3 post-treatment, respectively. In contrast, 86 and 80% of harems headed by non-VSX stallions contained foals in those years. Acquisition of pregnant mares appeared more likely than sneak copulations by bachelor stallions to account for foals in harems with a single stallion. However, most foals were born into harems that included a subordinate stallion, an occurrence that was undoubtedly exacerbated by the extended breeding season resulting from the sterility of the harem stallion. Thus, in comparing alternative reproductive tactics, bachelors appeared less successful than subordinate stallions within a harem. However, the highest reproductive success was achieved by the harem stallion, further demonstrating that alternative tactics are not equally profitable.

Abstract: We used an opportunistic review of photographs of different adult and juvenile horses walking, trotting, and cantering (n = 828) to compare the angle of the nasal plane relative to vertical in feral and domestic horses at liberty (n = 450) with ridden horses advertised in a popular Australian horse magazine (n = 378). We assumed that horses in advertisements were shown at, what was perceived by the vendors to be, their best. Of the ridden horses, 68% had their nasal plane behind the vertical. The mean angle of the unridden horses at walk, trot, and canter (30.7 ± 11.5; 27.3 ± 12.0; 25.5 ± 11.0) was significantly greater than those of the ridden horses (1.4 ± 14.1; ?5.1 ± ?11.1; 3.1 ± 15.4, P < 0.001). Surprisingly, unridden domestic horses showed greater angles than feral horses or domestic horses at liberty. We compared adult and juvenile horses in all 3 gaits and found no significant difference. Taken together, these findings demonstrate that the longitudinal neck flexion of the degree desirable by popular opinion in ridden horses is not a common feature of unridden horses moving naturally. Moreover, they suggest that advertised horses in our series are generally being ridden at odds with their natural carriage and contrary to the international rules of dressage (as published by the International Equestrian Federation). These findings are discussed against the backdrop of the established doctrine, which states that carrying a rider necessitates changes in longitudinal flexion, and in the context of the current debate around hyperflexion.