Environment shapes sleep patterns in a wild nocturnal primate.

Among primates, the suborder Haplorhini is considered to have evolved a consolidated monophasic sleep pattern, with diurnal species requiring a shorter sleep duration than nocturnal species. Only a few primate species have been systematically studied in their natural habitat where environmental variables, including temperature and light, have a major influence on sleep and activity patterns. Here we report the first sleep study on a nocturnal primate performed in the wild.

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

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.

Slow lorises (Nycticebus spp.) display evidence of handedness in the wild and in captivity.

It has been suggested that strepsirrhines (lemurs, lorises, and galagos) retain the more primitive left-hand preference, whilst monkeys and apes more regularly display a right-hand preference at the individual-level. We looked to address questions of laterality in the slow loris (Nycticebus spp.) using spontaneous observations of 7 wild individuals, unimanual tests in 6 captive individuals, and photos of 42 individuals in a bilateral posture assessing handedness at the individual- and group-level.