Acoustic structure of alarm calls in Indian sambar (Rusa unicolor) and Indian muntjac (Muntiacus vaginalis) in South Vietnam.

The alarm call acoustic structure and nonlinear vocal phenomena of the Indian sambar (Rusa unicolor) and northern Indian muntjac (Muntiacus vaginalis) have been analyzed in detail as well as their vocal behavior in response to mobbing humans under natural conditions of southern Vietnam. The alarm calls of sambars, tonal barks separated by large intervals, were produced by animals standing on the place and gazing at a potentially dangerous object. Muntjacs flee off in danger and produced a series of dull barks interrupted with short intervals from a distance. The alarm call frequencies were characterized for sambars and muntjacs. The results of our study have been compared with the published data on alarm calls of other Cervidae species.