There is some variation in the markings on both males and females of this species which has raised classification issues. Generally, the crown is blackish in both species; the tail is buffy to blackish with a black tip (Groves, 2001). Most of the body is yellow in colour. Weight differences: Males are between 700 to 1.1kg, Females are between 500 to 700gms.
Habitat and Distribution
Found in numerous habitats, this species is adaptable to mangrove, primary and secondary rainforest dependent upon fruit availability. (Baldwin, 1981). Generally preferring to occupy mid level canopy, (Hershkovitz in Mittermeier 1984) gave the distribution of this subspecies as “South of Rio Jurua’ – Amazonas and west of the Rio Purus – Guapore’, west to the Andes, in Brazil, Peru and Bolivia.
The Squirrel Monkey is often hunted for food. Habitat loss is also an issue although not at high levels. This species was in the past captured for use in the pet trade and also extensively used for medical research – this still does happen in some areas.
Squirrel Monkeys are described as frugivorous and insectivorous. They tend to consume a high level of fruit in the first part of the day and then search for insects as they day continues . Squirrel Monkeys in captivity have had some problems regarding infant birth size and deaths. In the wild, fruit availability was lowest during the first three to four months of pregnancy, greater just before and during the birth season and greatest at weaning time. Insects are the preferred food type – designed for protein consumption. As a result of this information, carbohydrate intake decreased the last two months of pregnancy. As a result of this information taken from wild squirrel monkey groups, a number of Zoos have developed “pregnancy diets” that are implemented two months prior to any suspected birth.
Breeding and Lifecycle
The Bolivian Squirrel Monkey, lives in large multi male, multi female groups which vary in size from less than 20 individuals to up to a few hundred animals in larger forests. For this reason the species is overall socially very tolerant except during breeding season when the males often become aggressive towards each other. In many social groups as breeding occurs and numbers increase, small bachelor groups often form naturally (Baldwin 1981), as the male offspring slowly start to hang on the periphery of the main group. Females are able to give birth from around 2 ½ years of age and the males are fully developed by the time they are 4 years old. Life expectancy is around 20 to 25 years of age.
Many organisations have traditionally housed squirrel monkeys in small groups with only one male and a few females, however as this species naturally occurs in large social groups, more institutions are developing exhibits and strategies to undertake a more natural approach to their captive management. Over the past few years, breeding of this species has almost ceased within the region due to a number of different reasons, however a recent importation of new animals and the potential for further acquisitions, it is hoped that Squirrel Monkeys will once again be a successful species within the Australasian region.
Mittermeier, R., Coimbra-Filho, A.,eds (1988), In Ecology and Behaviour of Neotropical Primates, Academia Brasilera de Ciencias, Washington.
Groves C, 2001, Primate Taxonomy, Library of Congress Cataloging-in-Publication Data, USA.