Habitat: Lowland and montane rain forests. Distribution: Mexico to South America Natural History Notes: Howler Monkeys, along with so many other primates, are classified as an endangered species. Characteristics: Mantled Howler Monkeys belong to the largests new world monkeys, males can weigh up to 22 lbs. They have black fur with longer golden yellow hair on their sides. The Mantled Howler Monkey lives in groups of 10 to 20 members, with usually one alpha male. However, there have been recordings of groups up to 40 members in size. Their diet consists mainly of fruits, leaves and flowers.