[1] Univ Gottingen, Courant Res Ctr Evolut Social Behav, D-37077 Gottingen, Germany
[2] Univ Leipzig, Inst Biol 2, D-04103 Leipzig, Germany
[3] Max Planck Inst Evolutionary Anthropol, D-04103 Leipzig, Germany
[4] Univ Utrecht, Dept Biol, NL-3508 TC Utrecht, Netherlands
[5] Chulalongkorn Univ, Fac Sci, Dept Biol, Primate Res Unit, Bangkok, Thailand