Advertising individual identity by mother and adolescent contact calls in Siberian wapiti Cervus elaphus sibiricus

Ethology. 2018. Vol. 124. No. 10. P. 733–742.

Sibiryakova O. V., Volodin I. A., Volodina E. V.

Individualistic contact calls facilitate mother-offspring reunion after separation. However, in many mammals both the acoustic structure and individuality of contact calls differ between mother and young. In contrast, in Siberian wapiti Cervus elaphus sibiricus, contact calls are similar in the acoustics between mother and young, whereas effects of this similarity on vocal individuality was not investigated. In this study, we analysed acoustic differences between closed-mouth (nasal) and open-mouth (oral) contact calls and examined individuality of the most usual oral calls of 19 Siberian wapiti (nine hinds and ten 5-6-month adolescents) emitted in response to mother-offspring separation. In the oral calls the values of frequency and power variables were higher than in the nasal calls. Calls of hinds and adolescents did not differ by the maximum fundamental frequency and duration, whereas the peak frequency was higher in the young. Discriminant function analysis (DFA) based on 11 acoustic variables of oral calls accurately classified to individual 92.5% of hind calls and 96.9% of adolescent calls (chi-square test for differences between hinds and adolescents, p=0.19). Variables mainly contributing to vocal identity (duration, start and maximum fundamental frequency) were the same in calls of mothers and adolescents. We conclude that similarities in the acoustics calls of mothers and adolescents mean that they do not differ in their potential for encoding individual identity, suggesting a mutual process of mother-offspring vocal recognition in Siberian wapiti.

Keywords: поведение животных, Animal behaviour, Акустическая коммуникация, Acoustic communication