The following article has been published online. A comparison of pectoral fin contact between two different wild dolphin populations KM Dudzinski, JD Gregg, CA Ribicc, SA Kuczaj Abstract: Contact behaviour involving the pectoral fin has been documented in a number of dolphin species, and various explanations about its function have been offered. Pectoral fin contact can take a variety of forms, and involves a number of body parts and movements, likely differing depending upon social or ecological context. For this study, we compare the pectoral fin contact behaviour of two species of wild dolphins: Indo-Pacific bottlenose dolphins (Tursiops aduncus) from around Mikura Island, Japan, and Atlantic spotted dolphins (Stenella frontalis) from The Bahamas. The two study populations exhibit surprising similarity in the ways in which pectoral fin contacts are used, despite differences in species and environmental conditions at the two sites. Differences in contact rates for calves between the two sites suggest that calf-focused aggression from adult dolphins is more prevalent at Mikura than in The Bahamas. Our results suggest that pectoral fin contact behaviour seems to be driven primarily by social pressures, and may be similar in function to allogrooming described in primates. A PDF file of our article is now available online through ScienceDirect at: http://dx.doi.org/10.1016/j.beproc.2008.11.011 or by emailing me at kdudzinski@dolphincommunicationproject.org This article can be cited in press as: Dudzinski, K.M., et al., A comparison of pectoral fin contact between two different wild dolphin populations. Behav. Process. (2008), doi:10.1016/j.beproc.2008.11.011 -- Kathleen M. Dudzinski, Ph.D. Director, Dolphin Communication Project www.dolphincommunicationproject.org Www.thedolphinpod.com email: kdudzinski@dolphincommunicationproject.org