Probable signature whistle production in Atlantic white‐sided (Lagenorhynchus acutus) and short‐beaked common (Delphinus delphis) dolphins near Cape Cod, Massachusetts

Abstract

Some delphinids produce a learned, individually specific tonal whistle that conveys identity information to conspecifics . These whistles, termed signature whistles, were first described by Caldwell and Caldwell (1965) and have been studied intensively over the past several decades . In common bottlenose dolphins (Tursiops truncatus) and potentially other species, signature whistles facilitate many ecologically-important behaviors, including individual recognition and maintenance of group cohesion (Janik & Slater, 1998). Additionally, signature whistle contours, or patterns of frequency change over time, can remain stable for several decades, aiding in long-term social bonds (Sayigh et al., 1990). Signature whistles account for approximately 38%-70% of all whistle production in freeswimming animals (Buckstaff, 2004;Cook et al., 2004;Watwood et al., 2005); this percentage can be up to 100% for

First identification of stereotyped whistle contour types by Pseudorca crassidens

“…However, information about SW derives mostly, from the common bottlenose dolphins ( Tursiops truncatus ; Bruck et al, 2022; Caldwell & Caldwell, 1965; Caldwell et al, 1990; Gridley et al, 2014; Janik & Sayigh, 2013; Rio et al, 2022). In addition to bottlenose dolphins, individually distinctive SW have been identified and described for eight other delphinid species (Rio, 2023a), namely: Indo‐Pacific bottlenose dolphins ( Tursiops aduncus ; Gridley et al, 2014), spinner dolphins ( Stenella longirostris ; Rio, 2023a), common dolphins ( Delphinus delphis ; Caldwell & Caldwell, 1968; Fearey et al, 2019), Atlantic spotted dolphins ( Stenella frontalis ; Caldwell & Caldwell, 1970), Pacific white‐sided dolphins ( Sagmatias obliquidens ; Caldwell et al, 1973), Atlantic white‐sided dolphins (Lagenorhynchus acutus ; Cones et al, 2023), Pacific humpback dolphins ( Sousa chinensis ; van Parijs & Corkeron, 2001), and Guiana dolphins ( Sotalia guianensis ; de Figueiredo & Simão, 2009).…”

“…Ten naïve independent observers (veterinary medical students), who had no previous experience with bioacoustics experiments, assessed a randomly chosen data subset to confirm the reliable identification of different PSW types. Each observer received five randomly chosen examples of all identified PSW types ( n = 8; Cones et al, 2023; Janik, 1999; Sayigh et al, 2007). They were instructed to split them into groups of five, based on contour similarity; no further guidance was given.…”