Photo Credit: Simon J Allen
We have a new paper out in the journal Bioacoustics that shows Welsh bottlenose dolphins produce high frequency signature whistles, the highest frequency recorded for the species so far.
Authors; Helen M. Hiley, Sarah Perry, Steve Hartley & Stephanie L. King
Abstract: Animal communication signals are diverse. The types of sounds that animals produce, and the way that information is encoded in those sounds, not only varies between species but can also vary geographically within a species. Therefore, an understanding of the vocal repertoire at the population level is important for providing insight into regional differences in vocal communication signals. One species whose vocal repertoire has received considerable attention is the bottlenose dolphin. This species is well known for its use of individually distinctive identity signals, known as signature whistles. Bottlenose dolphins use their signature whistles to broadcast their identity and to maintain contact with social companions. Signature whistles are not innate, but are learnt signals that develop within the first few months of an animal’s life. It is therefore unsurprising that studies which have characterized signature whistles in wild populations of bottlenose dolphins have provided evidence of geographic variation in signature whistle structure. Here, we describe the occurrence of signature whistles in a previously unexplored wild population of bottlenose dolphins in Cardigan Bay, Wales. We present the first occurrence of a signature whistle with an ultrasonic fundamental frequency component (>30 kHz), a frequency band that was not thought to be utilized by this species for whistle communication. We also describe the occurrence of an ultrasonic non-signature whistle. Our findings highlight the importance of conducting regional studies in order to fully quantify a species’ vocal repertoire, and call into question the efficacy of those studies that use restricted sampling rates.
The article can be found here: http://www.tandfonline.com/doi/full/10.1080/09524622.2016.1174885
Photo Credit: Donald McMullen/Dolphin Research Center
We are very pleased to announce the publication of our recent study on postpartum signature whistle production in bottlenose dolphins, published in the journal Marine Mammal Science.
Authors; Stephanie L. King, Emily Guarino, Katy Donegan, Jane Hecksher and Kelly Jaakkola.
Summary: Individual vocal signatures play an important role in facilitating maternal care in many animals. In those species where neonates are precocial immediately following parturition, the need for individual recognition between mother and offspring is paramount. In bottlenose dolphins such acoustic recognition signals, termed signature whistles, have been shown to be pivotal in mother-offspring recognition. Here we explored how female bottlenose dolphins used their signature whistle in the weeks leading up to and following the birth of their calves. We show that females significantly increased signature whistle production immediately after the birth of their female calves (LMER, P < 0.0001). Average signature whistle rate increased from 0.14 whistles/min to 0.78 whistles/min, representing a > five-fold increase in postpartum signature whistle production, with rates remaining high for four weeks after birth. Our findings complement those of Fripp and Tyack (2008), and offer further support to the imprinting hypothesis, where calves imprint on their mothers’ signature whistles immediately after parturition. The increase in maternal signature whistle use facilitates the calf’s recognition of its mother’s call before mother-calf separations occur. These results highlight the importance of postpartum signature whistle use in aiding mother-calf recognition in bottlenose dolphins and provide insight into one of the underlying mechanisms that aids mother-offspring recognition in species with precocial young.
You can access the paper here: http://onlinelibrary.wiley.com/doi/10.1111/mms.12317/full