How loud is a howler monkey's howl?
Howler monkey
As their name suggests, vocal communication forms an important part of their social behavior. They each have an enlarged basihyal or hyoid bone, which helps them make their loud vocalizations. Group males generally call at dawn and dusk, as well as interspersed times throughout the day. The main vocals consist of loud, deep guttural growls or "howls". Howler monkeys are widely considered to be the loudest land animal. According to Guinness Book of World Records, their vocalizations can be heard clearly for 3mi (4.8km).[7] The function of howling is thought to relate to intergroup spacing and territory protection, as well as possibly to mate-guarding.
Atelidae
These are arboreal and diurnal animals, with most species restricted to dense rain forest, although some howler monkey species are found in drier forests, or wooded savannah. They mainly eat fruit and leaves, although the smaller species, in particular, may also eat some small insects. They have the dental formula: 