The newly described Araguaian river dolphins, Inia araguaiaensis (Cetartyodactyla, Iniidae), produce a diverse repertoire of acoustic signals

, , , , , ,
1 BioMA - Biology and Conservation of Amazonian Aquatic Mammals, BioMA - Biology and Conservation of Amazonian Aquatic Mammals, Belém, Pará, Brazil
2 Graduate program in Theory and Research of Behavior, Universidade Federal do Pará, Belém, Pará, Brazil
3 Research Group on Amazonian Aquatic Mammals, Mamirauá Institute for Sustainable Development, Tefé, Amazonas, Brazil, Tefé, Amazonas, Brazil
4 Laboratory of Ornithology and Bioacoustics, Universidade Federal do Pará, Belém, Pará, Brazil
5 Department of Ecology, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
6 Laboratory of Bioacoustics and Cetacean Ecology, Universidade Federal Rural do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
7 Graduate Program in Animal Biology, Universidade Federal Rural do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
8 Department of Biology, University of Vermont, Burlington, Vermont, United States
DOI
10.7287/peerj.preprints.26962v2
Published
Accepted
Subject Areas
Animal Behavior, Biodiversity, Ecology, Zoology, Freshwater Biology
Keywords
boto, behavior, acoustic communication, mother-calf pairs, non-linear phenomena
Copyright
© 2018 Melo-Santos et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Melo-Santos G, Figueiredo Rodrigues AL, Tardin RH, de Sá Maciel I, Marmontel M, Da Silva ML, May-Collado LJ. 2018. The newly described Araguaian river dolphins, Inia araguaiaensis (Cetartyodactyla, Iniidae), produce a diverse repertoire of acoustic signals. PeerJ Preprints 6:e26962v2

Abstract

The recent discovery of the Araguaian river dolphin (Inia araguaiaensis) highlights how little we know about the diversity and biology of river dolphins. In this study, we described the acoustic repertoire of this newly discovered species in concert with their behaviour in free-ranging, human-habituated individuals. We analysed 393 signals that we classified into 13 types of tonal sounds (n=15) and 66 types of pulsed calls (n=378). The most common sounds were short two-component calls. Thirty-five percent (n=140) of these calls were emitted by calves as they reunited with their mothers suggesting a key role in mother-calf communication. Our findings show that the acoustic repertoire of river dolphins is far from simple. Furthermore, the calls described here are similar in acoustic structure to those produced by social delphinids, such as orcas and pilot whales. Uncovering the context in which these signals are produced may help understand the social structure of this species and contribute to our understanding of the evolution of acoustic communication in whales.

Author Comment

Change small erros on the numbers of figures.

Supplemental Information

Short two-component-calls produced by a calf of Araguaian boto

Short two-component-calls produced by a calf of Araguaian boto while contacting its mother, at the moment the calf was rubbing its head on the mather's belly

DOI: 10.7287/peerj.preprints.26962v2/supp-1

Short calls produced by an Araguaian boto

Short call produced by an Araguaian boto while interacting with humans at the market of Mocajuba, Tocantins River, Brazil

DOI: 10.7287/peerj.preprints.26962v2/supp-2

Long call with subharmonics produced by an Araguaian boto

Long call with subharmonics produced by an Araguaian boto while interacting with humans at the market of Mocajuba, Tocantins River, Brazil

DOI: 10.7287/peerj.preprints.26962v2/supp-3

Short call with subharmonics produced by an Araguaian boto

Short call with subharmonics produced by an Araguaian boto while interacting with humans at the market of Mocajuba, Tocantins River, Brazil

DOI: 10.7287/peerj.preprints.26962v2/supp-4

Whistle produced by an Araguaian boto

Whistle produced by an Araguaian boto while interacting with humans at the market of Mocajuba, Tocantins River, Brazil

DOI: 10.7287/peerj.preprints.26962v2/supp-5

Long two-component call produced by an Araguaian boto

Long two-component call produced by an Araguaian boto while interacting with humans at the market of Mocajuba, Tocantins River, Brazil

DOI: 10.7287/peerj.preprints.26962v2/supp-6

Araguaian boto calf videos url's

This is a link to a dropbox folder containing videos of an Araguaian boto female calf producing short two-component calls after reuniting with her mother, the call emission is followed by bubble streams, identifying the vocalizing animal. As the files are too long for uploading on Peer J database I am providing the link through this document

DOI: 10.7287/peerj.preprints.26962v2/supp-7