Multilevel animal societies can emerge from cultural transmission.
Multilevel societies, containing hierarchically nested social levels, are remarkable social structures whose origins are unclear. The social relationships of sperm whales are organized in a multilevel society with an upper level composed of clans of individuals communicating using similar patterns of clicks (codas). Using agent-based models informed by an 18-year empirical study, we show that clans are unlikely products of stochastic processes (genetic or cultural drift) but likely originate from cultural transmission via biased social learning of codas. Distinct clusters of individuals with similar acoustic repertoires, mirroring the empirical clans, emerge when whales learn preferentially the most common codas (conformism) from behaviourally similar individuals (homophily). Cultural transmission seems key in the partitioning of sperm whales into sympatric clans. These findings suggest that processes similar to those that generate complex human cultures could not only be at play in non-human societies but also create multilevel social structures in the wild.
Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, Canada, NS B3H 4J1.
Maurício
M
Cantor
Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, UCB 334, Ramaley Hall, Boulder, Colorado 80309, USA.
Lauren G
LG
Shoemaker
National Institute of Physics, College of Science, University of the Philippines Diliman, Quezon City 1101, Philippines.|Sustainable Fisheries Group, Bren School of Environmental Science and Management and Marine Science Institute, University of California Santa Barbara, 2400 Bren Hall, California 93106, USA.
Reniel B
RB
Cabral
School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, Georgia 30332-430, USA.
César O
CO
Flores
Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, Indiana 46556, USA.
Melinda
M
Varga
Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, Canada, NS B3H 4J1.
Hal
H
Whitehead
D000818:Animals; D001522:Behavior, Animal; D006608:Hierarchy, Social; D008962:Models, Theoretical; D012919:Social Behavior; D012925:Social Conformity; D000067570:Social Learning; D050661:Sperm Whale; D013269:Stochastic Processes; D014828:Vocalization, Animal