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

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 'harem' 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.

Population dynamics and social organization of sambar (Rusa unicolor unicolor) in Horton Plains National Park, Sri Lanka

“…would produce calves in July-August, as we have observed in HPNP. Present findings in HPNP are also supported bySavanth et al (2011) from Thrissur, Kerala, India, where sambar has shown a peak calving period closer to ours. Although we could record calving throughout the year in HPNP, dominant reproductive peaks shown by a majority of mature males in synchronous hard antler stage and mating be-…”

“…Following this peak mating behavior in November-December with an approximately eight-month gestation recorded in sambar hinds by Sankar and Acharya (2004) states have also reported a majority of mature stags in the hard antler stage during the same period, indicating apparent breeding seasonality (Ramesh et al, 2013). The synchrony of sambar mating behavior with the hard antler stage has been reported in many other regions of the world in addition to the Indian subcontinent (Dahlan & Dawend, 2013;Kierdorf et al, 2007;Ramesh et al, 2012), and has been explained by an increase of testosterone level in males (Savanth et al, 2011;Savanth & Saseendran, 2012;Weerasekera et al, 2020). A study conducted in the Manawatu flex swamp in New…”

“…According to Weerasekera et al (2020), the group size of sambar herds in HPNP is directly related to the monthly percentage of males in different antler stages, except during the calving seasons. Antlers in male sambar are indicative of the status of breeding activity and are important in dominancy display (Savanth et al, 2011;Weerasekera et al, 2020).…”

Body measurements and testosteron level of male Timor deer (Rusa timorensis) at various hierarchies

“…Only α-males showed increasing value in neck circumference. Savanth et al (2011) reported that the neck musculature of Sambar deer was larger during the rut season, especially those at the highest rank of dominance hierarchy. The increasing size of neck musculature resulted from rubbing antlers, an activity of scent marking.…”

“…Dilation of fibril muscle also need to be exercised to maintain muscle strength. Monfort et al (1993) reported that in Eld's deer stags, aggressive behavior increased rapidly along (Savanth et al, 2011).…”