Final answer:
Female langurs use various strategies such as confusing paternity by mating with multiple males and forming protective alliances to prevent infanticide from new dominant males.
Step-by-step explanation:
To prevent infanticide, female langurs engage in certain behaviors that discourage or mitigate aggressive actions typically by male langurs who take over a troop and may harm the offspring sired by previous male leaders. This disruption in the social structure can lead to dangerous situations for the young langurs, as incoming dominant males may attempt to kill them to bring the females back into estrus and sire their offspring. Female langurs may react to this threat through various strategies, such as mating with multiple males to confuse paternity, thereby reducing the likelihood that males will commit infanticide as they may be harming their offspring. Furthermore, they may also form protective coalitions or alliances with other females or friendly males to safeguard the young.