Alouatta palliata

The mantled howler (Alouatta palliata), or golden-mantled howling monkey, 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 monkeys, spider monkeys, woolly monkeys and muriquis. It is a member of the subfamily Alouattinae and genus Alouatta, the subfamily and genus containing all the howler monkeys. The species name is A. palliata; a pallium was a cloak or mantle worn by ancient Greeks and Romans. This refers to the long guard hairs, known as a 'mantle', on its sides. Three subspecies are recognized: Two additional subspecies of the mantled howler are sometimes recognised, but these are more generally recognised as subspecies of the Coiba Island howler, Allouatta coibensis. However, mitochondrial DNA testing of their status has been inconclusive: The mantled howler's appearance is similar to other howler monkeys of the genus Alouatta except for coloration. The mantled howler is primarily black except for a fringe of yellow or golden brown guard hairs on the flanks of the body earning the common name 'mantled' howler monkey. When the males reach maturity, the scrotum turns white. Females are between 481 and 632 mm (18.9 and 24.9 in) in body length, excluding tail, and males are between 508 and 675 mm (20.0 and 26.6 in). The prehensile tail is between 545 and 655 mm (21.5 and 25.8 in) long. Adult females generally weigh between 3.1 and 7.6 kg (6.8 and 16.8 lb), while males typically weigh between 4.5 and 9.8 kg (9.9 and 21.6 lb). Average body weights can vary significantly between monkey populations in different locations. The brain of an adult mantled howler is about 55.1 g (1.94 oz), which is smaller than that of several smaller monkey species, such as the white-headed capuchin. The mantled howler shares several adaptations with other species of howler monkey that allow it to pursue a folivorous diet, that is, a diet with a large component of leaves. Its molars have high shearing crests, to help it eat the leaves, and males have an enlarged hyoid bone near the vocal cords. This hyoid bone amplifies the male mantled howler's calls, allowing it to locate other males without expending much energy.