Breeding

Red howler monkeys can breed at any time of year, with both males and females pairing with a number of mates. The female gives birth 140 days after mating to a single baby, which is born fully furred and is able to cling to its mother's belly fur, so that she can still forage with the rest of the troop. As the baby gets older, it climbs onto its mother's back. The baby rides on its mother for at least one year and is not fully weaned until 18-24 months.

Young males are driven out of a troop when they reach sexual maturity. They then search for a new troop to take over. Having taken over a new troop, a male will often kill all the offspring of the previous dominant male to ensure that he does not waste time looking after another monkey's young, and so that only his genes get passed on.