Sleeping sites choice by a wild group of howler monkeys (Alouatta belzebul) in the Atlantic Forest of Brazil

Abstract

Study of primates sleeping habits is important to understand their behaviour and adaptations. Red-handed howler monkey is a new world monkey which is classified as Vulnerable in the IUCN red list. The present study aims to understand the choice of sleeping trees by these monkeys to facilitate the establishment of an adapted conservation plan. Indeed, data were collected in a fragmented landscape of the Atlantic Forest, following a wild monkey group from dawn to dusk. Trees criteria and monkeys behaviour were measured and tested. Moreover, this data were compared between rainy and dry days to know the impact of the rainfall on the sleeping behavior. Results show that red-handed howler monkeys sleep preferentially in one species of Pau-d'arco which is a big tree, higher than the other in the forest. This is an open tree. They sleep on average at 16,05 m (sd ± 2,09), which is significantly lower than the height where they rest during the day. Sleeping trees choice is correlated with density of food resources. They sleep together, very close. They come back in the same sleeping site but don't used a same tree several nights in a row. Choosing big open sleeping trees bring comfort to be together and allow to do monitoring of environment to avoid predators. Switch of sleeping trees is according with the avoiding parasite hypothesis and predator too. More, food resources seems to be an important criteria for choosing sleeping tree. Thus, this knowledge about "Alouatta belzebul" could allow to conservation implications for maintenance of this vulnerable primate species, with promoting of Pau-d'arco plantation in these landscapes of Atlantic forest.

Keywords

• conservation
• fragmented landscape
• red-handed howler monkey
• sleeping trees