Dear Marmam readers,<br><br>The following paper has recently been published in the Proceedings of the Royal Society B:<br><br>Randic, S., Connor, R. C., Sherwin, W. B., and Krutzen, M. (2012) A novel mammalian social structure in Indo-Pacific bottlenose dolphins (<i>Tursiops</i> sp.): complex male alliances in an open social network. Proceedings of the Royal Society B. doi: 10.1098/rspb.2012.0264<br>

<br>ABSTRACT:<br><br>Terrestrial mammals with differentiated social relationships live in ‘semi-closed groups’ that occasionally accept new members emigrating from other groups. Bottlenose dolphins (<i>Tursiops</i> sp.) in Shark Bay, Western Australia, exhibit a fission–fusion grouping pattern with strongly differentiated relationships, including nested male alliances. Previous studies failed to detect a group membership ‘boundary’, suggesting that the dolphins live in an open social network. However, two alternative hypotheses have not been excluded. The <i>community defence model</i> posits that the dolphins live in a large semi-closed ‘chimpanzee-like’ community defended by males and predicts that a dominant alliance(s) will range over the entire community range. The <i>mating season defence</i> model predicts that alliances will defend mating-season territories or sets of females. Here, both models are tested and rejected: no alliances ranged over the entire community range and alliances showed extensive overlap in mating season ranges and consorted females. The Shark Bay dolphins, therefore, present a combination of traits that is unique among mammals: complex male alliances in an open social network. The open social network of dolphins is linked to their relatively low costs of locomotion. This reveals a surprising and previously unrecognized convergence between adaptations reducing travel costs and complex intergroup–alliance relationships in dolphins, elephants and humans.<br>

<br><br>The paper can be accessed via the website: <a href="http://rspb.royalsocietypublishing.org/content/early/2012/03/20/rspb.2012.0264" target="_blank">http://rspb.royalsocietypublishing.org/content/early/2012/03/20/rspb.2012.0264</a><br>

<br>or via email requests to: Richard Connor (<a href="mailto:rconnor@umassd.edu" target="_blank">rconnor@umassd.edu</a>) or Srđan Randić (<a href="mailto:srdan.randic@u-psud.fr" target="_blank">srdan.randic@u-psud.fr</a>)<br>
<br><br>Best wishes,<br><br>
Srđan<br><br>-------------------------<br><br>Srdan Randic<br><br>Laboratoire Ecologie, Systématique et Evolution<br>Université Paris-Sud XI<br>Batiment 362<br>F-91405 Orsay Cedex<br>France