- 1Centre
for Evolutionary Biology, School of Animal Biology, University of
Western Australia, Crawley, 6009, Australia. stephanie.king@uwa.edu.au.
- 2Centre for Marine Futures, School of Animal Biology, University of Western Australia, Crawley, 6009, Australia.
- 3Biology Department, University of Massachusetts Dartmouth, North Dartmouth, MA, 02747, USA.
- 4Dolphin Research Center, 58901 Overseas Highway, Grassy Key, FL, 33050, USA.
Abstract
Two
recent papers by Kuczaj et al. (Anim Cognit 18:543-550, 2015) and
Eskelinen et al. (Anim Cognit 19:789-797, 2016) claim to have
demonstrated that (i) bottlenose dolphins (Tursiops truncatus)
cooperated to solve a novel task and (ii) vocal signals were important
for coordinating these cooperative efforts. Although it is likely that
bottlenose dolphins may share communicative signals in order to achieve a
common goal, we suggest that this has not been demonstrated in the
aforementioned studies. Here, we discuss the two main problems that
preclude any definitive conclusions being drawn on cooperative task
success and vocal communication from these studies. The first lies in
the experimental design. The 'cooperative task', involving an apparatus
that requires two dolphins to pull in opposite directions in order to
achieve a food reward, is not conducive to cooperation, but could
instead reflect a competitive 'tug-of-war'. It is therefore of
questionable use in distinguishing competitive from cooperative
interactions. Second, the suggestion that the occurrence of burst-pulsed
signals in this task was indicative of cooperation is disputable, as
(i) this study could not determine which dolphins were actually
producing the signals and (ii) this sound type is more commonly
associated with aggressive signalling in dolphins. We commend the
authors for investigating this exciting and topical area in animal
communication and cognition, but the question of whether dolphins
cooperate and communicate to solve a cooperative task remains as yet
unanswered
