When a weaker boy assumes defeat, he gets detained, disarmed, and then is freed to rejoin the tribe at a lower status. When a weaker girl assumes defeat, she gets knocked down, humiliated, and then is marked for life so she cant rejoin the tribe, or is made a corpse for others to jump on top and to be feed on. Boys fight their rivals. Girls fight their enemies. Defeats for boys mean demotion; for girls, total destruction. Stakes differ sharply.