Observations on Sambar Rusa unicolor (Cetartiodactyla: Cervidae) stags during hard and velvet stages of antler cycle in captivity

V Vishnu Savanth,K.S Anil,V Ramnath,A Prasad,P.C Saseendran,Justin Davis

doi:10.11609/jott.o2672.2128-35

Abstract

This research was carried out at the State Museum and Zoo, Thrissur, Kerala, India from June to October, 2009. The objective was to observe and record the physical and behavioural changes in Sambar Deer Rusa unicolor stags linked to their territorial display during various stages of the breeding cycle. In total, there were 70 Sambar in the enclosure, at the commencement of the study, of which 22 were males including 16 adult stags. Six stags were selected for the study. Observations were made by focal animal sampling technique. An ethogram was devised and behavioural patterns were indicated on it. The behavioural score derived from the ethogram was significantly higher in stags in their hard antler stage when compared to the stags in the velvet stage. The stags in the hard antler stage were more massive, had bigger antlers, darker coat colour, thicker neck, larger scrotum and maintained a larger â€˜haremâ€™ in comparison to the velvet stage stags which preferred a rather subdued life. The most dominant stags in the hard antler stage had up to 17 female members in his territory. As the stags in velvet entered the rut season, the dominant stag had up to 19 females in his territory. The study is expected to be useful to evolve strategies to identify and reduce a few males not contributing in breeding in any particular enclosure and thus curtail expenses in management of cervids in captivity.

Highlights

Behavioural variation in ungulate populations is an area of research, which could provide insights into the evolution of ungulate behaviour, and more generally, into the evolution of the process in individual decision-making (Isvaran 2005)
On the basis of decreasing order of ‘dominance hierarchy’ three of the Sambars namely H1, H2 and H3 were in the rut or hard antler stage, and others namely V1, V2 and V3 were in the later stages of velvet growth
Antler growth cycles are closely related to sexual cycles in stags and are directly attributable to variations in seasonal photoperiod influencing gonadal steroidogenic activity

Summary

Introduction

Behavioural variation in ungulate populations is an area of research, which could provide insights into the evolution of ungulate behaviour, and more generally, into the evolution of the process in individual decision-making (Isvaran 2005). One such behaviour is related to breeding, in the context of dominance hierarchy, factors enforcing changes in the hierarchy, the breeding cycle and maintenance of healthy populations in captive conditions. The present study is an attempt to record dominance hierarchy visà-vis different types of behaviour associated with body conditions and breeding display in a population of Sambar Deer Rusa unicolor maintained in the State Museum and Zoo, Thrissur in Kerala, and it provides some basal information that may be needed to evolve strategies to curtail the exploding population and reduce the cost of maintenance in captivity

Methods

Results

Conclusion