Howler monkeys have enlarged hyoid bones in their necks that help them produce loud vocalizations. Groups of males generally belt out loud guttural growls, or howls, at dawn and dusk, possibly as a way to protect their boundaries and guard their mates. Howler monkeys are considered to be the world's loudest land animals, and their chorus can be heard clearly through the dense rainforest from as far away as three miles (4.8 km), according to Guinness World Records.
Can you hear me now?
- Male howler monkeys have large throats and specialized, shell-like vocal chambers that help them crank up the volume. The message to other monkeys is clear: Back off.
- Howler monkeys are among the largest of the New World monkeys and one of only a few species of nest-building monkeys.
- These monkeys are native to South and Central American forests. They face threats from humans such as habitat destruction and being captured for relocation to zoos.