Loud calling in a female-dominated mammalian society: II. Behavioural contexts and functions of whooping of spotted hyaenas, Crocuta crocuta

Abstract

Spotted hyaenas use a loud call, the whoop. In this study, whoops served three main functions: (1) to display identity; (2) to request support; and (3) to convey information about the location of the caller. An analysis of ontogenetic changes revealed a common functional framework of loud calling for cubs and adults. Cubs primarily whooped to provide information about their location and to request support, while adults mainly whooped to display their identity, males more so than females. Females whooped during agonistic encounters with other female clan members and clashes with neighbouring clans, when locating offspring and when rallying group members to defend communal resources. Whooping in males was mainly used for inter- and intra-sexual display. Self-advertisement (vocal display) was the most common function of whooping at the communal den. Both sexes displayed vocally, but males called at higher rates than females. High-ranking females displayed vocally at a higher rate than subordinates to assert their priority of access to kills in the clan's core range. Breeding females also whooped to deter potentially infanticidal non-clan members from approaching cubs at the communal den. Spotted hyaenas are polygynous, and male vocal display rates are an important component of inter-male competition. Display rates may also influence mate choice by the dominant and more aggressive females. Dominant males exerted more effort when whooping than subordinates by having higher display rates, more often using the energetically more costly type S whoop, and producing more calls per bout. All top ranked males are old, and have probably held long tenure in the clan. If females only mate with dominant males they may select mates on the basis of age, familiarity, display effort or a combination of these factors.