Fig 4. After male replacement, new males showed two strategies,
either aggression or tolerance, which would bring different reproductive
success. When males adopted a strategy of aggression, they obtained
increased reproductive success from killing infants because they sired
the next offspring of victims’ mother sooner. However, they completely
lost benefits as lactating females emigrated if the first set of attack
did not kill the offspring. Therefore, male would benefit from their
strategies because (a) male tenures are longer than inter-birth
intervals of female if keeping mothers and their unweaned infant in
their social unit, (b) tenures of tolerant male are longer tenures than
those of aggressive male if the male tolerate the unweaned infant
without attack.