Degree Year


Document Type

Thesis - Oberlin Community Only

Degree Name

Bachelor of Arts




Angela J. Roles

Committee Member(s)

Roger H. Laushman
Laela S. Sayigh


Bioacoustics, Marine biology, Tursiops truncatus, Bottlenose dolphin, Vocalization, Vocal copying, Signature whistles, Acoustic behavior, Playback experiment


Bottlenose dolphins (Tursiops truncatus) communicate primarily through vocalizations, of which two primary types are signature whistles (function to convey identity information) and non- signature whistles (functions presently unknown). They are also adept at copying other dolphins’ whistles. Currently, knowledge about copying is limited. My project aims to further the understanding of the contexts of whistle copying in bottlenose dolphins. I investigated whether bottlenose dolphins produce vocal copies in response to a stimulus – playbacks of signature whistles or non-signature whistles, using subsets of playback experiments generated between 1989 and 2014 at Sarasota Bay (Florida) health assessments. Using Raven Pro 1.6, I visually identified all signature and non-signature whistles and potential copies that occurred in each of 59 thirteen-minute playback periods. Copies were independently verified by six naïve observers scoring the similarity of response whistles to stimuli on a five-point scale; twelve whistles with a mean score above three were considered “verified copies”. I examined the association between copy presence/absence and contextual variables such as sex, stimulus whistle type, and recording context using Fisher’s Exact tests. Copy production was not significantly associated with dolphin sex (P = 0.474; odds ratio = 0.539), nor with recording context (P = 0.139; odds ratio = 3.48). Copy production was significantly associated with stimulus type (P = 0.031; odds ratio = 8.41). Additionally, sex and recording context were significantly associated (P = 0.015; odds ratio = 0.247). Future work may investigate variation among individuals in copy production and the role of copies in facilitating certain behaviors.