Sleep patterns, daytime predation, and the evolution of diurnal sleep site selection in lorisiforms

Svensson, Magdalena, S., Nekaris, K. Anne-Isola, Bearder, Simon K., Bettridge, Caroline M., Butynski, Thomas M., Cheyne, Susan M., Das, Nabajit, de Jong, Yvonne A., Luhrs, Averee M., Luncz, Lydia V., Maddock, Simon T., Perkin, Andrew, Pimley, Elizabeth R., Poindexter, Stephanie A., Reinhardt, Kathleen D., Spaan, Denise, Stark, Danica J., Starr, Carly R. and Nijman, Vincent (2018) Sleep patterns, daytime predation, and the evolution of diurnal sleep site selection in lorisiforms. American Journal of Physical Anthropology, 166 (3). pp. 563-577. doi:10.1002/ajpa.23450

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Objectives Synthesize information on sleep patterns, sleep site use, and daytime predation at sleep sites in lorisiforms of Asia and Africa (10 genera, 36 species), and infer patterns of evolution of sleep site selection. Materials and methods We conducted fieldwork in 12 African and six Asian countries, collecting data on sleep sites, timing of sleep and predation during daytime. We obtained additional information from literature and through correspondence. Using a phylogenetic approach, we established ancestral states of sleep site selection in lorisiforms and traced their evolution. Results The ancestral lorisiform was a fur‐clinger and used dense tangles and branches/forks as sleep sites. Use of tree holes and nests as sleep sites emerged ∼22 Mya (range 17–26 Mya) in Africa, and use of bamboo emerged ∼11 (7–14) Mya in Asia and later in Africa. Fur clinging and some sleep sites (e.g., tree holes, nests, but not bamboo or dense tangles) show strong phylogenetic signal. Nests are used by Galagoides, Paragalago, Galago and Otolemur; tree holes by Galago, Paragalago, Sciurocheirus and Perodicticus; tangles by Nycticebus, Loris, Galagoides, Galago, Euoticus, Otolemur, Perodicticus and Arctocebus; all but Sciurocheirus and Otolemur additionally sleep on branches/forks. Daytime predation may affect sleep site selection and sleep patterns in some species of Nycticebus, Galago, Galagoides, Otolemur and Perodicticus. Most lorisiforms enter their sleep sites around sunrise and leave around sunset; several are active during twilight or, briefly, during daytime. Conclusion Variations in sleep behavior, sleep patterns and vulnerability to daytime predation provide a window into the variation that was present in sleep in early primates. Overall, lorisiforms use the daytime for sleeping and no species can be classified as cathemeral or polycyclic.

Item Type: Article
Article Type: Article
Additional Information: This is the peer reviewed version of the following article: Svensson MS, Nekaris KAI, Bearder SK, et al. Sleep patterns, daytime predation, and the evolution of diurnal sleep site selection in lorisiforms. Am J Phys Anthropol. 2018;166:563–577., which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Uncontrolled Keywords: Sleep sites; Social organization; Strepsirhine
Subjects: Q Science > QH Natural history
Q Science > QL Zoology
Divisions: Schools and Research Institutes > School of Education and Science
Research Priority Areas: Place, Environment and Community
Depositing User: Rhiannon Goodland
Date Deposited: 14 Jan 2019 15:34
Last Modified: 31 Aug 2023 08:58

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