% pubman genre = article @article{item_2585649, title = {{Nocturnal activity in wild chimpanzees (Pan troglodytes): Evidence for flexible sleeping patterns and insights into human evolution}}, author = {Tagg, Nikki and McCarthy, Maureeen and Dieguez, Paula and Bocksberger, Ga{\"e}lle and Willie, Jacob and Mundry, Roger and Stewart, Fiona and Arandjelovic, Milica and Widness, Jane and Landsmann, Anja and Agbor, Anthony and Angedakin, Samuel and Ayimisin, Ayuk Emmanuel and Bessone, Mattia and Brazzola, Gregory and Corogenes, Katherine and Heegde, Martijn ter and Deschner, Tobias and Dilambaka, Emmanuel and Eno-Nku, Manasseh and Eshuis, Henk and Goedmakers, Annemarie and Granjon, Anne-C{\'e}line and Head, Josephine S. and Hermans, Veerle and Jones, Sorrel and Kadam, Parag and Kambi, Mohamed and Langergraber, Kevin and Lapeyre, Vincent and Lapuente, Juan and Lee, Kevin and Leinert, Vera and Maretti, Giovanna and Marrocoli, Sergio and Meier, Amelia and Nicholl, Sonia and Normand, Emmanuelle and Ormsby, Lucy Jayne and Piel, Alex and Robinson, Orume and Sommer, Volker and Tickle, Alexander and Ton, Els and van Schijndel, Joost and Vanleeuwe, Hilde and Vergnes, Virginie and Wessling, Erin G. and Wittig, Roman M. and Zuberbuehler, Klaus and K{\"u}hl, Hjalmar S. and Boesch, Christophe}, language = {eng}, issn = {0002-9483}, doi = {10.1002/ajpa.23478}, publisher = {Wiley-Liss, Inc.}, address = {New York, NY}, year = {2018}, date = {2018-07}, abstract = {{Abstract Objectives We investigated occurrences and patterns of terrestrial nocturnal activity in wild chimpanzees (Pan troglodytes) and modelled the influence of various ecological predictors on nocturnal activity. Methods Data were extracted from terrestrial camera{-}trap footage and ecological surveys from 22 chimpanzee study sites participating in the Pan African Programme: The Cultured Chimpanzee. We described videos demonstrating nocturnal activity, and we tested the effects of the percentage of forest, abundance of predators (lions, leopards and hyenas), abundance of large mammals (buffalos and elephants), average daily temperature, rainfall, human activity, and percent illumination on the probability of nocturnal activity. Results We found terrestrial nocturnal activity to occur at 18 of the 22 study sites, at an overall average proportion of 1.80{\textpercent} of total chimpanzee activity, and to occur during all hours of the night, but more frequently during twilight hours. We found a higher probability of nocturnal activity with lower levels of human activity, higher average daily temperature, and at sites with a larger percentage of forest. We found no effect of the abundance of predators and large mammals, rainfall, or moon illumination. Discussion Chimpanzee terrestrial nocturnal activity appears widespread yet infrequent, which suggests a consolidated sleeping pattern. Nocturnal activity may be driven by the stress of high daily temperatures and may be enabled at low levels of human activity. Human activity may exert a relatively greater influence on chimpanzee nocturnal behavior than predator presence. We suggest that chimpanzee nocturnal activity is flexible, enabling them to respond to changing environmental factors.}}, journal = {{American Journal of Physical Anthropology}}, volume = {166}, number = {3}, pages = {510--529}, }