The woolly spider monkey, or muriqui, is one of the most threatened primate species in the world. Because of deforestation in their natural habitat - the Atlantic coastal forests of southeastern Brazil - the muriquis are confined to less than 3 percent of their original range. In 1987, there were only a dozen forest fragments known to support a total muriqui population of about 500. But the muriqui is starting to rebound. As of 1998, at least 20 forests are known to support at least 1,000 muriquis. This book traces the natural history of the muriqui from its scientific discovery in 1806 to its current, highly endangered status. Karen Strier provides a case study of this scientifically important primate species by balancing field research and ecological issues.