Water Scarcity, Distribution, and Quality as Drivers of Lemur Behavior

Abstract

Because water is essential for life, when it is scarce, it may be one of the most important drivers of animal behavior. Despite its clear importance, water is relatively poorly studied in terms of its impact on primate behavior, and previous research has been limited to observational studies. This dissertation takes a combined experimental and observational approach to study behavior related to water acquisition in captive and wild lemurs. Specifically, I investigated how several dimensions of water sources influence lemur behavior, including their parasite transmission risk, spatial distribution, and predation risk. In experiments, I manipulated the fecal contamination of water with several species of lemurs in captivity at the Duke Lemur Center, and found that lemurs strongly preferred clean to feces-contaminated water in captivity (Chapter 2). I expanded this initial study to a more comprehensive examination of the impact of water scarcity on the behavior of wild red-fronted lemurs (Eulemur rufifrons) in Kirindy Forest, Madagascar. This wild study population requires drinking water to survive, but water is extremely limited during the dry season. I experimentally manipulated water availability in the habitat by introducing artificial water sources, and I tracked how changes to the distribution of water influenced the ranging patterns of the lemurs recorded by GPS collars. Lemur groups shifted the intensity of their habitat use relative to natural and experimental water availability (Chapter 3). Using a similar experimental approach to the study in captivity, I determined that wild, water-limited lemurs also preferred to drink clean water. Based on lemur groups’ selection of natural water sources as measured with camera traps, wild lemurs also selected water sources with lower fecal contamination more frequently, but with some constraints. Lemurs were more likely to return to waterholes and returned to them after shorter time intervals when they had lower levels of fecal contamination in the areas around them. However, lemurs’ natural waterhole choices reflected that fecal contamination was a secondary factor determining water source selection, behind travel distance (Chapter 4). Finally, I examined how predation risk, i.e. the presence of fossa (Cryptoprocta ferox) and Madagascar harrier hawks (Polyboroides radiatus), influenced red-fronted lemurs’ spatiotemporal patterns of waterhole use. Red-fronted lemurs used waterholes at times of day when predators were least likely to be present (Chapter 5). This study, with its combined experimental and observational approach, identifies water as an important factor that shapes wild primate behavior. I found that lemurs were flexible in their responses to changes in water distribution, parasite risk, and predation risk. I suggest that water should be the focus of future behavioral research in primates, especially given the relevance of water for human evolution and the potential for climate change and human land use to further alter water availability.