Bio Facts: Howler, Southern Black
Southern Black Howler
Northeastern Argentina, eastern Bolivia, eastern and southern Brazil and Paraguay
Forests, especially semi-deciduous and gallery forests
Adult length: 22 to 36 in (55.8 to 91.4 cm); tail length: 23 to 36 in (58.4 to 91.4 cm); weight: 15 to 22 lbs (7 to 10 kg); coloration: the adult male is black; adult females and juveniles of both genders are overall whitish to yellowish-buff; appearance: wide, side-opening nostrils, no pads on their rumps, and a prehensile tail. They have beards and long, thick hair.
Up to 15 years in the wild; up to 20 in captivity
About 2.5 years
In the wild, they eat top canopy leaves, together with fruit, buds, flowers, and nuts; in the Zoo, they are fed scientifically developed, commercially available primate diet, assorted greens, vegetables, fruits, and browse.
IUCN – Least Concern; CITES – Appendix II
Black howlers monkeys commonly sleep or rest up to 70 percent of the day, making it one of the least active monkeys in the New World. They are herbivorous, eating mostly leaves, and occasionally fruit, such as figs. They generally prefer walking and climbing to running or leaping. The prehensile tail is very strong and acts as a fifth limb, allowing the monkeys greater versatility when climbing and allowing them greater safety from the occasional fall from high branches. Because their limb structure makes terrestrial movement awkward, they spend most of their time in the trees and only come down for water during dry spells. Otherwise, the monkeys drink by wetting their hand on a moist leaf and then licking the water off of their hand.
They live in groups of 3 to 19 individuals (usually 7 to 9). There are usually one to three males for every seven to nine females in a group. The mating system appears promiscuous among the members of the group. Physical fighting among group members is infrequent and generally of short duration. However, serious injuries can result. Both males and females may fight with each other but physical aggression is even rarer between sexes. Unlike most New World monkeys, in which one sex remains in natal or birth groups, juveniles of both sexes emigrate from their natal groups. An adult howler monkey could spend the majority of its life in association with non-kin.
Gestation length is 187 days. Studies have shown that younger females have gestation length of 10 to 12 months while more mature mothers have gestation length of only 7 to 10 months. Females give birth to one offspring per birth and care for infants for about one full year before mating again. Infants are about 4.4 oz (125 g) at birth. Black howlers practice allomothering, mothers allow other females to carry, groom and protect infants. Adult males are also sometimes seen alloparenting. Young males are not allowed to handle infants since they often mistreat or even kill them.
Named for their vocalizations, they may be heard most often around sunrise and sunset. This “chorus” sounds much more like roaring than howling, and it announces the howlers’ position so as to avoid conflict with other groups. The call can be heard up to 3.1 mi. (5 km) away.
They have an enlarged basihyal or hyoid bone which helps them make their loud vocalizations. Group males generally call at dawn and dusk as well as interspersed times throughout the day. The main vocals consist of loud, deep guttural growls or “howls.” Howler monkeys are widely considered to be the loudest land animal. According to Guinness Book of World Records, their vocalizations can be heard clearly for 3 miles (4.8 km). It is hypothesized that the function of howling relates to intergroup spacing and territory protection, as well as possibly mate-guarding.
Black Howlers have large salivary glands that help to break down the tannins in the leaves before they reach the gut. The molar teeth are particularly adapted for their chewing leaves through shearing.
In their phylogenetic analysis using the cytochrome b gene, Nascimento et al. (2005) showed that populations of Alouatta caraya from Santa Cruz, Bolivia (Chaco) are differentiated from those in various localities in the state of Mato Grosso and (one specimen) Goiás further north. This indicates the possibility of two taxa of the black howler monkey, rather than just one.
To the Mayas of the Classic Period, howler monkeys were the divine patrons of the artisans, especially scribes and sculptors. Copán is famous for its representations of Howler Monkey Gods. Two howler monkey brothers play a role in the 16th century myth of the Maya Hero Twins included in the Popol Vuh, a corpus of mytho-historical narratives of the Post Classic Quiché kingdom in Guatemala’s western highlands.
Threats to howler monkeys include human predation, habitat destruction and being captured for captivity as pets or zoo animals. Black howlers are threatened by clear-cutting and selective logging since they are heavily reliant on the biodiversity of predominantly primary forests for their diet. Some populations are more threatened than others. According to the Priority Primate Conservation Projects for the Neotropical Region from the Revised Global Action Plan for Primate Conservation, black howlers in the Argentine provinces of Formosa, Misiones, Salta and Corrientes are threatened and a high priority for conservation. Hunting pressure ranges from moderate in locations such as San Jose, Bolivia to none in northern Argentina.
This species is listed as Least Concern considering its large range, presence in several national parks, and ability to adapt to modified habitats. At present, it is not likely that the species, while declining, warrants listing in a threatened category under criterion A. Although its habitat is very fragmented, populations can live in relatively small areas and disturbed forest. This species is threatened by habitat loss due to agricultural development for soy and cattle ranching in the Brazilian cerrado, soy in the Bolivian Chiquitano, and small-scale farms and cattle ranching in Argentina. Some subsistence hunting occurs across its range.
Jacksonville Zoo History:
This species was brought in for the first time in 2003 in preparation for the 2004 opening of the Range of the Jaguar exhibit area.