The howler monkey group contains 15 different species of howler monkeys, all of which are native to the forests of Central and South America.Howler monkeys live within groups of five to fifteen individuals with usually about three males and the rest all females.ow Many: Non Threatened Howler monkeys are on the largest new world primates and are recognized as the loudest land animal in the world. They’ve earned both this reputation and this name from the unique enlarged hyoid bone in the throats of howler monkeys, that are the keys to their characteristic “howling”.