Cooperation or dolphin ‘tug-of-war’? Comment on Kuczaj et al. and Eskelinen et al.
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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.
- Aureli F, de Waal FB (2000) Natural conflict resolution. University of California Press, BerkeleyGoogle Scholar
- Caldwell MC, Caldwell DK (1967) Intraspecific transfer of information via the pulsed sound in captive odontocete cetaceans. In: Bullock RG (ed) Animal sonar systems—biology and bionics. Laboratoire Physiologie Acoustique, Jouy-en-Josas, pp 879–936Google Scholar
- Crawford MP (1937) The cooperative solving of problems by young chimpanzees. Comp Psychol Monogr 14:1–88Google Scholar
- Ridgway SH, Moore PW, Carder DA, Romano TA (2014) Forward shift of feeding buzz components of dolphins and belugas during associative learning reveals a likely connection to reward expectation, pleasure and brain dopamine activation. J Exp Biol 217:2910–2919. doi:10.1242/jeb.100511 CrossRefPubMedGoogle Scholar