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Howler Monkey - Loudest Land Animal

Gaynor Borade
The largest of the monkeys categorized as the 'New World Monkeys' and the loudest land animals, howler monkeys range in size from 56 to 92cm. They are native to the dense forests of Central and South America.
The howler monkey belongs to the sub family Alouattinae, of which currently fifteen species are recognized. Its tail is as long as its main frame, which is up to 92 cm. It has a prehensile tail and is large, but slow moving. They enjoy an average lifespan of anywhere between 15 and 20 years.
They communicate with a loud whooping sound they make, that can cover up to 3 miles, through the dense forest. No wonder they are named 'howler'! They live in groups and are threatened by captivity, by humans.
The interesting social behavior trait observed in them is the powerful vocal communication. The medium of communication is exercised within the group and out of it too, as a warning, announcement, or a mere show of presence.

Communication and Behavior

The 'howl' of the monkey sounds like a powerful roar. The roaring sound is a distinct feature of the males. In the females, the vocalization sounds like a grunt, like that of the pig.
The sound is generated by the enlarged basihyal bone or the hyoid bone, that is a distinct feature in the species. The size of the basihyal bone is what enables the howler to produce the roars! They are considered the loudest land animals and they are observed to have trichromatic color vision.
They are folivores, feeding only on the top leaves of the canopy formed by the tall trees in the dense forests and fruits, nuts, and flowers. 
They move on all fours or quadrapedally and hold on to branches with both or one hand and the tail. This style of movement is used at all times and it is rare that it uses the strength of its tail to support the whole body.
Their tail is very strong. These monkeys rarely leave the trees and are the least active of all the species on the planet, resting almost 80% of the time. They limit all activities to the branches and forks of the tall evergreens. The number of females is greater than the number of males in a group.
Groups are formed by juveniles, both males and females, who wander or emigrate from their natal groups. Hence, in a group, the adults are not related. Fighting for a short while and then reconciling among group members is frequent. They become very aggressive in captivity.

Significance in Human Culture

When the Maya ruins were discovered in Copan, these monkeys were represented in the art, as gods!. The art depict grave and solemn features, like as if they were guardians of some consecrated ground. Their role in the life of the Mayas and the acknowledgement of their presence is ample to understand the kind of importance given to these beautiful creatures.
It is also called 'Congo' in Costa Rica and Nicaragua, while in Belize, they are referred to as 'baboons'. However, the latter is despite the fact that the monkey is in no way related to the primate that is usually identified by that name.


This monkey belongs to the categorized family of Atelidae and is studied by researchers under the 'palliata' group of primates. Research reveals that although they are not easy pets to maintain, because of the size of their droppings and the roaring sound they are capable of producing, they enrich the forests of Central and South America by their presence.
The howler monkey is distinct in features and terrain. This beautiful creature needs to be saved from unnecessary captivity and abuse. Human encroachment is taking its toll on the forest cover and the longevity of the groups within needs to be guaranteed, for a richer, more diverse wildlife population.