Dear MARMAMERS, On behalf of my co-authors, I am pleased to announce the following publication in Proceedings of the Royal Society B: Calves as social hubs: dynamics of the social network within sperm whale units By: Shane Gero, Jonathan Gordon, and Hal Whitehead Abstract: It is hypothesized that the primary function of permanent social relationships among female sperm whales (Physeter macrocephalus) is to provide allomothers for calves at the surface while mothers make foraging dives. In order to investigate how reciprocity of allocare within units of sperm whales facilitates group living, we constructed weighted social networks based on yearly matrices of associations (2005-2010) and correlated them across years, through changes in age and social role, to study changes in social relationships within seven sperm whale units. Pairs of association matrices from sequential years showed a greater positive correlation than expected by chance, but as the time lag increases, the correlation coefficients decreased. Over all units considered, calves had high values for all measured network statistics, while mothers had intermediate values for most of the measures, but high values for connectedness and affinity. Mothers showed sharp drops in Strength and Connectedness in the first year of their new calves' lives. These broad patterns appear to be consistent across units. Calves appeared to be significant nodes in the network of the social unit, and thus provide quantitative support for the theory in which communal care acts as the evolutionary force behind group formation in this species. The article is available online here: http://rspb.royalsocietypublishing.org/content/280/1763/20131113.abstract?si d=6da378fe-a56a-4b28-a1e1-6f7ffb63acee This publication emanates from The Dominica Sperm Whale Project. For more publications from this research program, please visit: http://www.thespermwhaleproject.org MEDIA: Press Material Available here: http://www.thespermwhaleproject.org/dswppress.html All our best, Shane Gero ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dr. Shane Gero Founder | Lead Researcher The Dominica Sperm Whale Project <mailto:shane@thespermwhaleproject.org> shane@thespermwhaleproject.org <http://www.thespermwhaleproject.org/> www.thespermwhaleproject.org facebook_logo20 <https://twitter.com/DomWhale> Twitter_2012_bird_icon 20 <https://plus.google.com/117645839450808338401> google_plus_logo20 <http://www.thespermwhaleproject.org/> DSWP email banner
