There are six species, two of which are considered endangered.
Howlers are large monkeys with prehensile tails and bearded faces.
Fur colors ranges from bright reddish to brown to black. The names come from their most distinctive feature a ferocious, loud, and according people who have been awakened from sleep by howlers, almost unearthly voice that echoes throughout the rainforest at sunrise and sunset. Male howlers have specialized throat structures that, like a megaphone, amplify their calls so they resonate for nearly a mile through the rainforest. 1998 Passport to Knowledge. All Rights Reserved.