The squeaking vocalization of grey wolves (Canis lupus): individuality in a close-range affiliative mammalian vocalisation

Abstract

Abstract Wolves (Canis lupus) frequently use the close-range squeaking vocalization, a soft, multi-unit, high-pitched tonal vocalisation. We examined the social and movement contexts of the occurrence and acoustic characteristics of squeaking from videotapes of pack-reared, pack-living captive wolves living in semi-natural conditions at the Canadian Centre for Wolf Research over a three-year period. We only examined squeaking vocalisations for which the sender and potential receiver(s) could be determined. Wolves squeaked in many contexts, especially when approaching other wolves in prosocial and food contexts. Some wolves squeaked more than others. Acoustically, squeaking vocalisations were individually identifiable, primarily through frequency characteristics. Contextual use suggests that squeaking conveys the friendly motivation of an approaching wolf and in aggressive situations, a motivation to defuse or decrease aggression. This close-range vocalisation may play an important role in controlling and coordinating social interactions within the pack.