Noisiest land animal

The world's noisiest land animals are the howler monkeys (Alouatta) of Central and South America. The males have an enlarged bony structure at the top of the windpipe which enables the sound to reverberate, and their fearsome screams have been described as a cross between the bark of a dog and the bray of an ass increased a thousandfold. Once in full voice they can be heard clearly up to4.8 km (3 miles) away.