Importance of a species’ socioecology: Wolves outperform dogs in a conspecific cooperation task

Sarah Marshall-Pescinia,b,1, Jonas F. L. Schwarza, Inga Kostelnika, Zsófia Virányia,b, and Friederike Rangea,b Author Affiliations aWolf Science Center, Messerli Research Institute, University of Veterinary Medicine, Medical University of Vienna, University of Vienna, 1210 Vienna, Austria; bComparative Cognition, Messerli Research Institute, University of Veterinary Medicine, Medical University of Vienna, University of Vienna, 1210 Vienna, Austria Edited by Frans B. M. de Waal, Emory University, Atlanta, GA, and approved September 5, 2017 (received for review May 31, 2017) Abstract Significance A popular hypothesis is that during the course of domestication, dogs acquired a tamer temperament, showing increased tolerance and cooperative inclinations compared with their wolf relatives. This “domestication effect” is suggested to mirror how humans evolved a more tolerant and cooperative nature compared with chimpanzees. However, whereas wolves rely heavily on cooperation for hunting, pup-rearing, and territorial defense, dogs’ reliance on cooperation is much reduced. Here we compared similarly raised and kept wolves and dogs on a cooperative string-pulling task and found that, in line with the different socioecology of the two species, wolves better cooperate with their conspecifics than dogs. Furthermore, cooperation in wolves was more successful among partners of similar rank and with a close social bond. Abstract A number of domestication hypotheses suggest that dogs have acquired a more tolerant temperament than wolves, promoting cooperative interactions with humans and conspecifics. This selection process has been proposed to resemble the one responsible for our own greater cooperative inclinations in comparison with our closest living relatives. However, the socioecology of wolves and dogs, with the former relying more heavily on cooperative activities, predicts that at least with conspecifics, wolves should cooperate better than dogs. Here we tested similarly raised wolves and dogs in a cooperative string-pulling task with conspecifics and found that wolves outperformed dogs, despite comparable levels of interest in the task. Whereas wolves coordinated their actions so as to simultaneously pull the rope ends, leading to success, dogs pulled the ropes in alternate moments, thereby never succeeding. Indeed in dog dyads it was also less likely that both members simultaneously engaged in other manipulative behaviors on the apparatus. Different conflict-management strategies are likely responsible for these results, with dogs’ avoidance of potential competition over the apparatus constraining their capacity to coordinate actions. Wolves, in contrast, did not hesitate to manipulate the ropes simultaneously, and once cooperation was initiated, rapidly learned to coordinate in more complex conditions as well. Social dynamics (rank and affiliation) played a key role in success rates. Results call those domestication hypotheses that suggest dogs evolved greater cooperative inclinations into question, and rather support the idea that dogs’ and wolves’ different social ecologies played a role in affecting their capacity for conspecific cooperation and communication. cooperation dogs wolves domestication comparative cognition Footnotes 1To whom correspondence should be addressed. Email: Sarah.Marshall@vetmeduni.ac.at. Author contributions: S.M.-P., Z.V., and F.R. designed research; S.M.-P., J.F.L.S., and I.K. performed research; S.M.-P. and F.R. analyzed data; and S.M.-P. and F.R. wrote the paper. The authors declare no conflict of interest. This article is a PNAS Direct Submission. This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1709027114/-/DCSupplemental. Published under the PNAS license.