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.

Vocalization toward conspecifics in silver foxes (Vulpes vulpes) selected for tame or aggressive behavior toward humans.

We examined the production of different vocalizations in three strains of silver fox (unselected, aggressive, and tame) attending three kinds of behavior (aggressive, affiliative, and neutral) in response to their same-strain conspecifics. This is a follow-up to previous experiments which demonstrated that in the presence of humans, tame foxes produced cackles and pants but never coughed or snorted, whilst aggressive foxes produced coughs and snorts but never cackled or panted. Thus, cackle/pant and cough/snort were indicative of the tame and aggressive fox strains respectively toward humans. Wild-type unselected foxes produced cough and snort toward humans similarly to aggressive foxes. Here, we found that vocal responses to conspecifics were similar in tame, aggressive and unselected fox strains. Both cackle/pant and cough/snort occurred in foxes of all strains. The difference in the use of cackle/pant and cough/snort among these strains toward humans and toward conspecifics suggest that silver foxes do not perceive humans as their conspecifics. We speculate that these vocalizations are produced in response to a triggering internal state, affiliative or aggressive, that is suppressed by default in these fox strains toward humans as a result of their strict selection for tame or aggressive behavior, whilst still remaining flexible toward conspecifics.

[Indicators of emotional arousal in vocal emissions of the humans and nonhuman mammals].

Human speech is not homologous to animal vocalizations, but these two different communication systems overlap in the area of expression of emotional arousal. The latter can be revealed in any mammalian vocal emissions: in human speech, in infant crying, and in calls of animals. Animals are able to perceive information about emotional arousal from human speech emissions and, in their turn, the humans are able to estimate emotional arousal from vocalizations of animals. Numerous studies conducted with many mammal species suggest the presence of vocal indicators of emotional arousal shared by the humans and nonhuman mammals. Here we appraise parameters used for description of call structures, overview fundamental studies constituting a framework for understanding the relationships between call structures and degrees of emotional arousal in mammals, and provide a synthesis of the available data allowing to establish integral vocal indicators of emotional arousal in the humans and nonhuman mammals.