Tick‐defense grooming patterns of two sympatric Tibetan ungulates

Abstract

AbstractGrooming is an important behavioral defense against tick infestation for ungulates. The ‘programmed grooming model' explains the endogenous regulation of tick‐defense grooming and predicts different inter‐ and intra‐specific grooming patterns owing to the body size principle. Here, we studied the summer grooming behaviors of two sympatric Tibetan ungulates, to explore whether or not body size principle works inter‐ and intra‐specifically. The ungulates were sexually and body‐size dimorphic Tibetan antelopes (Pantholops hodgsonii) with body weight of c. 33 kg and sexually dimorphic but body‐size monomorphic Tibetan gazelle (Procapra picticaudata) with body weight of c. 14 kg. Group size was also included in our negative binominal regression model to determine whether or not the ungulates groomed more or less with the increasing group size. Results showed that large Tibetan antelopes groomed much less than small Tibetan gazelles inter‐specifically. Intra‐specifically, sex–age significantly affects the grooming rate of Tibetan antelopes. The largest adult males groomed the least, whereas the smallest fawns groomed the most. However, this sex–age effect is not found in Tibetan gazelle: males and females groomed similarly. These findings indicate that body size principle is fully supported inter‐ and intra‐specifically. Positive group size effect on grooming is observed in Tibetan gazelle, suggesting that released vigilance time from group size effect is probably transferred to grooming. From a conservation point of view, we suggest further studies on the testosterone effect on grooming patterns during the rut as well as on tick biology on the plateau.