Matrilineal Fidelity, not Group Conformity, Explains Stability of a Chimpanzee Social CustomWrangham, RW, Koops, K, Machanda, ZP, Bernard, AB, Brazeau, NF, Donovan, R, Rosen, J, Wilke, C, Otali, E, Muller, MNJanuary 2016PDF Cite DOI