Preliminary evidence for signature and copied whistles among spinner dolphins in the Southwest Atlantic Ocean: Beacon purpose?

Abstract

In order to evaluate strategies of cohesion in a fission-fusion society, the occurrence of signature and copied whistles were investigated in free-ranging spinner dolphins, Stenella longirostris. Through an one-element hydrophone array towed over the Brazilian continental shelf break, a group of approximate 400 dolphins were recorded at 96 kHz/24 bits while navigating. The preliminary results demonstrated 218 similar signals that fit into previous definitions of signature or copied whistles. These whistles were produced in bouts with an inter-whistle interval of 0.066—11.56 s (mean ± SD: 2.66 ± 2.72) that varied from 2 to 32 repetitions comprising six different contour shapes. Thus, these data support previous hypothesis that these signals are important units in the dolphin’s repertoire. It may also suggests a potential use on individual direction and localization, where repeated contours could be acting as a beacon to direct and locate the animals within the group. Additional research to ascertain the natural function of these vocalizations may clarify the basis for acoustic badges of membership and group organization of this cosmopolitan species.

Infrasound as a Cue for Seabird Navigation

“…A classic example is provided by bacteria orienting in a chemical gradient field (Benhamou, 2010). The presence of acoustic beacons is supported by empirical (e.g., Moron and Andriolo, 2015) and experimental studies (e.g., Shettleworth and Sutton, 2005;Stansbury et al, 2015). For instance, sound made by conspecifics has been shown to act as a beacon in wood frogs Lithobates sylvaticus (Bee, 2007), and spinner dolphins Stenella longirostris (Moron and Andriolo, 2015).…”

Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) Whistle Sound by Denoising Spectra with Discrete Wavelet Transform (DWT)

“…Values obtained more noise in treatment after a meal that is in the image 11 shown in black. Complex of Discrete Wavelets Transform (DWT) [16,17] may provide similar benefits, but we have not yet explored them thoroughly in the context of mass spectrometry data. An orthogonal (decimated) discrete wavelet transform (DWT) was used to study SELDI data derived from the serum of prostate cancer patients according to Qu Y, et al [18][19][20][21].…”

Spectral analysis using Haar wavelet (original signal, denoised signal, residual signal) and source level (SL) for whistle sound of dolphin (Tursiops aduncus) in captivity

“…Likewise, a microphone can be buried in the ground, or immersed in water if it is put in a waterproof container, but will give similarly poor performance due to the similarly bad acoustic impedance match (Miller and Dawson, 2009). The Studies made both in captivity and in the field are therefore important for our understanding of animal echolocation and how it evolved Lubis et al, 2016a;Lubis et al, 2016b;Moron and Andriolo, 2015;Wulandari, 2016;Lubis, 2016). The vocalizations with the underwater behavior of dolphins has proved difficult due to the lack of underwater access to animals and life history, sex, and relationship information.…”