Golden-headed lion tamarins are a small primate species that have been listed as endangered (EN) by the IUCN. This species of marmoset is endemic to the Mata Atlântica and is found only on the cocoa coast of Bahia. The population decline is caused by habitat destruction, especially in the 20th century. The remaining habitats are highly fragmented and in large parts subject to multiple anthropogenic influences. Lion tamarins have only been able to survive because cacao is grown in traditional agroforestry, the cabruca, within their original habitat. Thereby, cocoa grows as understorey in the shade of the native forest. Cabrucas can be used as habitat by lion tamarins if specific key tree species are present, providing food and sleeping sites. By now, cabrucas represent a large part of the remaining habitats or connect them with each other. Despite the fact that traditional cacao cultivation has conserved much of the biodiversity of the Mata Atlântica, cabrucas are subject to different management practices, which has a major impact on biodiversity and also has a crucial influence on their suitability as habitat for lion tamarins. In a long-term monitoring project, golden-headed lion tamarins are observed by using radio collars to decipher how cabrucas are used and which key factors are crucial. This will help to determine which management practices are necessary for a the long-term survival of lion tamarins. The results will be used to create a guideline for cocoa farmers on how to manage cabrucas so that they are maintained as habitat for lion tamarins and new habitats are created.