Vocal exchanges of signature whistles in bottlenose dolphins (Tursiops truncatus)

Abstract

Bottlenose dolphins (Tursiops truncatus) produce individually distinctive vocalizations-referred to as ''signature whistles''-that are thought to function as an individual and conspecific recognition system for maintenance of consistent contact between individuals. Observations and playback experiments were conducted at aquariums to study these whistle-vocal exchanges in bottlenose dolphins. Temporal patterns of vocalization were examined by analyzing the intercall intervals between two consecutive whistles. When a second individual produced a call that was different from the first individual's vocalization, most of these calls were shorter than 1 s. However, when two consecutive calls were produced by the same individual, the second call rarely occurred within 1 s of the first. These results suggest that a second whistle may be produced by a different caller in response to the first whistle; however, in the case of an absence of a response, the first caller is likely to give further whistles. The results of this acoustic analysis show that the dolphins used in this study mostly used signature whistles during the recorded vocal exchanges.

Vocalisations of the bigeye Pempheris adspersa: characteristics, source level and active space

“…In captivity, the vocal activity of the bigeye peaked at dusk and remained relatively high throughout the night, which corresponds well with the nocturnally active nature of this species (Mooi, 2000 Koda et al, 2008;Nakahara and Miyazaki, 2011;Sugiura, 2007) and birds (Cortopassi and Bradbury, 2006;Sharp and Hatchwell, 2006), the ability to maintain group cohesion using contact calls has been reported as biologically advantageous in a number of respects (Kondo and Watanabe, 2009). For example, calls could contain details about individuality and distance.…”

Review of Underwater and In-Air Sounds Emitted by Australian and Antarctic Marine Mammals

“…Much of the literature focuses on whistles and geographic differences [151,152,156,163,174,253,270,276,286,[289][290][291][292][293][295][296][297][298]300,302]. Biphonic whistles have been reported [299].…”

“…Bottlenose dolphins develop signature whistles during the first few months of their lives and emit these when meeting conspecifics; they also copy signature whistles of others interpreted as "calling others" [294,296,299,302,[304][305][306][307][308][309][310][311][312][313].…”

The role of signature whistle matching in bottlenose dolphins, Tursiops truncatus

“…A rapid response may be perceived as an aggressive act (Beecher, Campbell, Burt, Hill, & Nordby, 2000;Searcy & Beecher, 2009), whereas a long interval between signals may not be seen as a response to the first signal. Studies on a variety of species show that, in general terms, the timing of call production appears to be governed by temporal rules whereby animals reply to a signal within a short time interval (Kureta, 2000;Masataka & Biben, 1987;Nakahara & Miyazaki, 2011;Sugiura, 1993). For example, in nightingales, Luscinia megarhynchos, response latencies in vocal matching interactions are much shorter when song types are matched than when they are not (Geberzahn, Hultsch, & Todt, 2013).…”