This way, one troop can constantly inform another of its precise location, thus avoiding an energetically costly squabble over resources. Due to such an unbalanced sex ratio, fierce sexual competition exists between and within red howler troops. Red howler males, which are expelled from their natal troop upon reaching sexual maturity, are forced to invade an outside group and gain admittance. Once they have accomplished this, they violently kill any infants present in the group. By killing infants in a newly invaded troop, a male can mate quickly and ensure that the new offspring of the group are his own.
Mothers do try to protect their offspring against assaulting males.
The mating behavior of red howlers is another interesting aspect of their social interactions. Males and females often form consortships, an unusually close spatial relationship, before any sexual exchange has begun. Once these associations are established, sexual solicitations begin. Although seductive behaviors can be performed by both sexes, the female most often takes on the aggressive role. When attempting to attract a male, the female approaches him and moves her tongue rhythmically.