The discovery of the ‘transient’ male Tibetan wild ass: alternative ‘sneaky’ mating tactics in a wild equid?

Abstract

Male asses usually consist of two classes, social bachelors and solitary, territorial males. However, our observations of the Tibetan wild ass (Equus kiang) suggested a third class may exist. Unexpectedly, unidentified males were often found courting females within another male’s territory. To test our hypothesis that a new social class existed, we compared 12 social behaviours among three putative groups. The third male-type spent less time herding and demonstrating flehmen, while spending more time retreating, trotting and in proximity of females, where they were more likely to engage in courtship and urine-marking. Based on increased time spent among females within other territories, the most courtship events, and minimal time invested in each courtship, they appear to employ ‘sneaky’ mating tactics. We discuss whether these ‘transient’ males are demonstrating an adaptive alternative mating strategy, or whether these behaviours result from a discrete developmental stage of bachelors unready to challenge a rival.

Social Class and Group Size as Predictors of Behavior in Male Equus kiang

“…Among the most prominent behaviors, Territorial males rested less and browsed less than Bachelors or Transients. These deficits may have been opportunity costs for the time necessary to defend their territories against the often-intruding Transient males (Kannan et al, 2016). Additionally, Territorial males may have rested less because they were defending more productive, greener patches that attract female visitations.…”

“…We conducted observations from dawn to dusk using binoculars with a Cannon 70D SLR Camera and a Sigma 150-500mm telephoto lens that recorded HD video with 21.2 Mp resolution at a distance of 400 -500 m (Kannan et al, 2016). This observer distance was selected because it is twice the distance (200 m) required to avoid observer presence influencing the behavior of focal animals.…”

“…They are found in harsh, remote, high-altitude areas where human populations have not been well established (Fox & Bårdsen, 2005). Therefore, we have limited knowledge about this species, and no known behavioral assays or activity budgets have been produced other than reports of foraging behavior as it varies with vegetation quality and seasonal abundance (St-Louis & Côté, 2012) and an examination of the frequency of social behaviors in males from three social classes, territorial males, bachelors and 'transients' (Kannan et al, 2016). Sharma et al(2004) has described kiang habitat selection in Upper Nepal, while resource selection and area-use has been quantitated in the presence and absence of livestock by Hussain, Qureshi, and Rawat (2010).…”

“…Different classes within genders may also differ dramatically in their respective investment into particular behaviors. While constructing our first activity budgets, we learned that there were three social classes of male (Kannan et al, 2016): social bachelors, solitary territorial males, and 'sneaky' transient males. The latter class represented either an alternative reproductive strategy or a transitional state between bachelors who were not yet ready to challenge a rival.…”