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 3 mi (4.8 km). The function of howling is thought to relate to intergroup spacing and territory
protection, as well as possibly to mate-guarding .