On the Behavioural Biology of the Mainland Serow: A Comparative Study

SIMPLE SUMMARY: Serows Capricornis spp. are solitary, elusive, forest-dwelling goat-antelopes, allegedly the closest ancestral forms to wild sheep and goats (Caprinae). Their behaviour and ecology have been largely overlooked so far, although they could be useful to understand the roots of early ritualisation of weapons, i.e., horns. The activity rhythms, marking behaviour, and social interactions of captive mainland serows have been described and quantified. Activity peaked in mid-afternoon and late night, whereas resting and ruminating were the highest at noon and twilight. The two sexes used different marking sites and marking frequencies. A total of 33 social behaviour patterns were observed: 18 patterns concerned agonistic behaviour, whereas 15 patterns were relevant to courtship behaviour. An evolutionary comparison across Caprinae species with unritualised piercing horns, inclusive of serows, suggests that inter-sexual direct forms of aggressive behaviour are used significantly more often than indirect ones, except for chamois. Thus, Chamois Rupicapra spp. would be confirmed as the most advanced genus in terms of an early ritualisation of weapons, i.e., strongly hooked horns. Conversely, horns of the goral Nemorhaedus spp. and the serow lie on the same plane of the frontal bones, thus making possible the usage of a dominance display through frontal pushing. ABSTRACT: Comparative behavioural studies help reconstruct the phylogeny of closely related species. In that respect, the serows Capricornis spp. occupy an important position as they have been assumed to be the closest forms to the ancestors of Caprinae. In spite of that, information on the behavioural repertoire of the mainland serow Capricornis sumatraensis is exceedingly poor. In this paper, we report data on the activity rhythms and social behaviour of rutting mainland serows in captivity (Central Thailand, January 1986; January–February 1987). Activity was bimodal with peaks in mid-afternoon and late night. Resting and ruminating peaked at noon and twilight. Four patterns of marking behaviour were observed out of a total of 1900 events. Males and females were found to use different marking sites and frequencies. A total of 33 social behaviour patterns were observed: 18 patterns concerned agonistic behaviour, whereas 15 patterns were relevant to courtship behaviour. A comparison across Caprinae species with unritualised piercing weapons (i.e., Capricornis, Naemorhedus, Rupicapra, Budorcas, and Hemitragus) has shown that inter-sexual direct forms of aggressive behaviour are used significantly more often than indirect ones, but for chamois, confirming Rupicapra spp. as the most advanced genus among them in terms of an early ritualisation of weapons. Conversely, horns of the goral Nemorhaedus spp. and the serow lie on the same plane of the frontal bones, thus making possible the usage of a dominance display through frontal pushing.