Hominoid primates show an evolutionary predisposition toward male-enforced ethnocentrism.

Evidence

Considering only closely related primates in the hominoid clade, there are a number of other common and relevant features of social organization, including: (a) the existence of closed social networks or what might be called ingroups, (b) communal territoriality, (c) male domination of intergroup relations, (d) the male domination of hostile and antagonistic relations between groups, and (e) the male domination of stalking, attacking, and of killing outgroup males (Ghiglier, 1989; Wrangham, 1987). This list suggests that the hominoid clade appears to be predisposed towards an ethnocentric orientation in which boundary maintenance towards outgroups is largely enforced by males. — John T. Jost and Jim Sidanius, Political Psychology, 3262

Categorization

• XREF: Resonates with the moral panic / modesty policing material — historically male-coded enforcement of ingroup/outgroup boundaries.
• DEEPTHINKING: Bear with this claim — male-coded intergroup violence present across all great apes is a genuinely paradigm-grappling proposition for theories of war and patriarchy.