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Matrosova V.A.,Moscow State University | Volodin I.A.,Moscow State University | Volodina E.V.,Moscow Zoo | Vasilieva N.A.,RAS Severtsov Institute of Ecology
Naturwissenschaften | Year: 2010

The questions of individuality and stability of cues to identity in vocal signals are of considerable importance from theoretical and conservation perspectives. While individuality in alarm calls has been reported for many sciurids, it is not well-documented that the vocal identity encoded in the alarm calls is stable between different encounters with predators. Previous studies of two obligate hibernating rodents, speckled ground squirrels Spermophilus suslicus, and yellow ground squirrels Spermophilus fulvus demonstrated that, after hibernation, most individuals could not be identified reliably by their alarm calls. Moreover, in most speckled ground squirrels, individual patterns of alarm calls changed progressively over as little as 2 weeks. However, these previous data have been obtained using the collection of alarm calls from trapped animals. Here, we examined ten free-ranging dye-marked yellow ground squirrels to determine whether their alarm calls retain the cues to individuality between two encounters of surrogate predators (humans), separated on average by 3 days. Discriminant function analysis showed that the alarm calls of individual yellow ground squirrels were very similar within a recording session, providing very high individual distinctiveness. However, in six of the ten animals, the alarm calls were unstable between recording sessions. Also, we examined ten dye-marked individuals for consistency of acoustic characteristics of their alarm calls between the encounters of humans, differing in techniques of call collection, from free-ranging vs trapped animals. We found differences only in two variables, both related to sound degradation in the environment. Data are discussed in relation to hypotheses explaining the adaptive utility of acoustic individuality in alarm calls. © 2010 Springer-Verlag.

Matrosova V.A.,Moscow State University | Blumstein D.T.,University of California at Los Angeles | Volodin I.A.,Moscow State University | Volodina E.V.,Moscow Zoo
Naturwissenschaften | Year: 2011

In addition to encoding referential information and information about the sender's motivation, mammalian alarm calls may encode information about other attributes of the sender, providing the potential for recognition among kin, mates, and neighbors. Here, we examined 96 speckled ground squirrels (Spermophilus suslicus), 100 yellow ground squirrels (Spermophilus fulvus) and 85 yellow-bellied marmots (Marmota flaviventris) to determine whether their alarm calls differed between species in their ability to encode information about the caller's sex, age, and identity. Alarm calls were elicited by approaching individually identified animals in live-traps. We assume this experimental design modeled a naturally occurring predatory event, when receivers should acquire information about attributes of a caller from a single bout of alarm calls. In each species, variation that allows identification of the caller's identity was greater than variation allowing identification of age or sex. We discuss these results in relation to each species' biology and sociality. © 2011 The Author(s).

Dubrovsky V.Y.,Moscow Zoo
Zoologicheskii Zhurnal | Year: 2016

The number of small mammals was registered using traps and pitfalls on Shokalsky Island (72°55′ N, 74°20′ E) during 20 days in August 2014. A total of 157 skulls from pomarine skua (Stercorarius pomarinus) pellets were examined. Only Siberian lemming (Lemmus sibiricus Kerr 1792) was identified. Trapping cylinders were used for the work in river valleys and flat interfluves. According to these data, the total number and large proportion of young non-breeding males were higher in the river valleys. The same habitats and drift-woods at the valley wall were investigated using break-back traps. Juvenile individuals were not found using this technique. The population structure in the river valleys was similar to that in the flat interfluve. In the drift-woods compared to the other habitats, the number of small mammals was 2 times higher, and the proportion of breeding females was greater.

Kudryavtsev S.V.,Moscow Zoo | Latyshev V.A.,Moscow Zoo
Russian Journal of Herpetology | Year: 2015

The first reliable information regarding successfully long term captive husbandry and breeding of Dragon Snake, Xenodermus javanicus Reinhardt, 1836 in Moscow Zoo is presented. © 2015 Folium Publishing Company.

Volodin I.A.,Moscow State University | Lapshina E.N.,Moscow State University | Volodina E.V.,Moscow Zoo | Frey R.,Leibniz Institute for Zoo and Wildlife Research | Soldatova N.V.,Ecocenter Djeiran
Ethology | Year: 2011

Like many other gazelles, goitred gazelles (Gazella subgutturosa) are capable of calling either through the nose or through the open mouth. In particular, juvenile goitred gazelles provide a convenient model for contrasting acoustic characteristics of nasal and oral calls, and for estimating their communicative functions. In this study, acoustic variables (formants, fundamental frequency, duration and power quartiles) of 480 oral and 483 nasal calls, recorded from 20 (9 male, 11 female) individually identified captive juvenile goitred gazelles, were examined for their potential to encode sex and identity of the caller. Discriminant function analysis revealed an equally high potential of oral and nasal calls to encode sex, whereas encoding the individual identity was significantly more accurate for oral calls. Sex was encoded exclusively in formants, whilst individual identity was encoded in a combination of all investigated variables. No correlation was found between body mass and values of any acoustic variable. Analyses controlling for age and sex revealed higher average values for all investigated variables of oral calls compared to nasal calls. We discuss the results in relation to the source-filter theory, mother-offspring communication and production mechanisms of nasal and oral calls in mammals. © 2011 Blackwell Verlag GmbH.

Volodina E.V.,Moscow Zoo | Matrosova V.A.,Moscow State University | Volodin I.A.,Moscow State University
Bioacoustics | Year: 2010

In most mammals, adults produce relatively low frequency vocalizations compared to those of juveniles. This rule is not maintained however at least in four species of ground squirrels, whose juveniles call at the adult's fundamental frequency. These findings have been obtained however with separate sets of juveniles and adults and no data is available concerning the ontogeny linked to these differences. Here we analyze the acoustic structure of alarm calls of the same Yellow Spermophilus fulvus and Speckled S. suslicus ground squirrel individuals, recorded as pups and as adults after hibernation. We found the fundamental frequencies of adults within the same frequency ranges as those of pups, in spite of the significant difference in body mass. In ground squirrels, severing the relationship between body size and call frequency removes some vocal cues to age. We discuss some functional hypotheses advanced to explain manipulations with fundamental frequencies in ground squirrels and other animals, and suggest the lack of data for discussing the mechanisms of such vocal tuning. © 2010 AB Academic Publishers.

Frey R.,Leibniz Institute for Zoo and Wildlife Research | Volodin I.,Moscow State University | Volodina E.,Moscow Zoo | Carranza J.,University of Cordoba, Spain | Torres-Porras J.,University of Cordoba, Spain
Journal of Anatomy | Year: 2012

Roaring in rutting Iberian red deer stags Cervus elaphus hispanicus is unusual compared to other subspecies of red deer, which radiated from the Iberian refugium after the last glacial maximum. In all red deer stags, the larynx occupies a permanent low mid-neck resting position and is momentarily retracted almost down to the rostral end of the sternum during the production of rutting calls. Simultaneous with the retraction of the larynx, male Iberian red deer pronouncedly protrude the tongue during most of their rutting roars. This poses a mechanical challenge for the vocal tract (vt) and for the hyoid apparatus, as tongue and larynx are strongly pulled in opposite directions. This study (i) examines the vocal anatomy and the acoustics of the rutting roars in free-ranging male C. e. hispanicus; (ii) establishes a potential mechanism of simultaneous tongue protrusion and larynx retraction by applying a two-dimensional model based on graphic reconstructions in single video frames of unrestrained animals; and (iii) advances a hypothesis of evaporative cooling by tongue protrusion in the males of a subspecies of red deer constrained to perform all of the exhausting rutting activities, including acoustic display, in a hot and arid season. © 2012 The Authors Journal of Anatomy © 2012 Anatomical Society.

Frey R.,Leibniz Institute for Zoo and Wildlife Research | Volodin I.,Moscow State University | Volodina E.,Moscow Zoo | Soldatova N.V.,Ecocenter Djeiran | Juldaschev E.T.,Ecocenter Djeiran
Journal of Anatomy | Year: 2011

Similar to male humans, Homo sapiens, the males of a few polygynous ruminants - red deer Cervus elaphus, fallow deer Dama dama and Mongolian gazelle Procapra gutturosa- have a more or less enlarged, low-resting larynx and are capable of additional dynamic vocal tract elongation by larynx retraction during their rutting calls. The vocal correlates of a large larynx and an elongated vocal tract, a low fundamental frequency and low vocal tract resonance frequencies, deter rival males and attract receptive females. The males of the polygynous goitred gazelle, Gazella subgutturosa, provide another, independently evolved, example of an enlarged and low-resting larynx of high mobility. Relevant aspects of the rutting behaviour of territorial wild male goitred gazelles are described. Video and audio recordings served to study the acoustic effects of the enlarged larynx and vocal tract elongation on male rutting calls. Three call types were discriminated: roars, growls and grunts. In addition, the adult male vocal anatomy during the emission of rutting calls is described and functionally discussed using a 2D-model of larynx retraction. The combined morphological, behavioural and acoustic data are discussed in relation to the hypothesis of sexual selection for male-specific deep voices, resulting in convergent features of vocal anatomy in a few polygynous ruminants and in human males. © 2011 The Authors. Journal of Anatomy © 2011 Anatomical Society of Great Britain and Ireland.

Volodin I.A.,Moscow State University | Volodina E.V.,Moscow Zoo | Lapshina E.N.,Moscow State University | Efremova K.O.,Moscow State University | Soldatova N.V.,Ecocenter Djeiran
Animal Cognition | Year: 2014

The potential for vocal modification in mammals has recently been of great interest. This study focuses on the potential for vocal matching in juvenile and adolescent goitred gazelles Gazella subgutturosa that were group housed as part of an animal management programme. Two groups of animals (16 and 19 unrelated individuals, respectively) were recorded at two different ages, juvenile and adolescent, regarding 20-25 calls per individual per age; each group was evaluated in a separate year. Vocal similarity of group members compared to non-members was prominent in both ages, but higher in juveniles. Individual identity was prominent in both ages and higher in adolescents. The more prominent vocal indicators of group membership in juveniles could be related to their higher social dependence compared to adolescents. The more individualized calls of adolescents could be a mechanistic consequence of more stable growth at older age. Our results suggest vocal plasticity of goitred gazelles under social influences. These data add to recent evidence about domestic goat kids Capra hircus, suggesting that vocalizations of species that are not capable of imitation are more flexible than previously thought. © 2013 Springer-Verlag Berlin Heidelberg.

Klenova A.V.,Moscow State University | Volodin I.A.,Moscow State University | Volodina E.V.,Moscow Zoo | Postelnykh K.A.,Oka Crane Breeding Center
Behaviour | Year: 2010

Voice breaking is a process associated with puberty of human males that also occurs in adolescence in some birds. This study reports the jump-like vocal changes occurring during voice breaking in adolescent red-crowned cranes (Grus japonensis). We investigated acoustic parameters of chirp and trill calls during vocal ontogenesis from hatching to the age of 1.5 years in 17 male and 31 female captive red-crowned cranes and compared them with definitive calls of 5 male and 8 female conspecific adults. During voice breaking, trills and chirps of both sexes contained two non-overlapping independent fundamental frequencies: the upper one, representing the retained juvenile frequency, and the lower one, the newly attained adult frequency. Before voice breaking, the calls contained only the upper frequency, whereas after it only the lower one. Voice breaking occurred between the age of 7 and 11.5 months. We test whether sex, dates of birth and body mass gain are associated with voice breaking and speculate whether voice breaking triggers the disruption of the parent-chick bond or vice versa, or both events are driven by a third, yet unidentified trigger. © Koninklijke Brill NV, Leiden, 2010.

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