The mantled howler (Alouatta palliata) is a species of howler monkey, a type of New World monkey, from Central and South America. It is one of the monkey species most often seen and heard in the wild in Central America. It takes its “mantled” name from the long guard hairs on its sides.

The mantled howler is one of the largest Central American monkeys, and males can weigh up to 9.8 kg (22 lb). It is the only Central American monkey that eats large quantities of leaves; it has several adaptations to this folivorous diet. Since leaves are difficult to digest and provide less energy than most foods, the mantled howler spends the majority of each day resting and sleeping. The male mantled howler has an enlarged hyoid bone, a hollow bone near the vocal cords, which amplifies the calls made by the male, and is the reason for the name “howler”. Howling allows the monkeys to locate each other without expending energy on moving or risking physical confrontation.

The mantled howler lives in groups that can have over 40 members, although groups are usually smaller. Most mantled howlers of both sexes are evicted from the group they were born in upon reaching sexual maturity, resulting in most adult group members being unrelated. The most dominant male, the alpha male, gets preference for food and resting places, and mates with most of the receptive females. The mantled howler is important to the rainforest ecology as a seed disperser and germinator. Although it is affected by deforestation, it is able to adapt better than other species, due to its ability to feed on abundant leaves and its ability to live in a limited amount of space.

• The mantled howler belongs to the New World monkey family “Atelidae”, the family that contains the “Howler monkey” “Spider monkey” “Woolly monkey” “Muriqui”. It is a member of the subfamily “Alouattinae” , the subfamily and genus containing all the howler monkeys. The species name is A. palliata was a cloak or mantle worn by ancient Ancient Greece & Ancient Rome. This refers to the long guard hairs, known as a “mantle”, on its sides.
  subspecies are recognized:
• Ecuadorian mantled howler: in Colombia, Costa Rica, Ecuador, Panama and Peru;
• Golden-mantled howler: in Costa Rica, Guatemala, Honduras and Nicaragua;
• Mexican howler” , in Mexico and Guatemala.

Two additional subspecies of the mantled howler are sometimes recognised, but these are more generally recognised as subspecies of the Coiba Island howler, as mitochondrial DNA testing of their status has been inconclusive:

• Azuero howler: On the Azuero peninsular on  Panama;
• Alouatta coibensis coibensis: in Panama and and Jicaron, off the Pacific coast of Panama