Illustration (IMAGE) Max-Planck-Gesellschaft Caption Accelerometers are deployed to non-invasively measure sleep behavior in a group of wild baboons. Mounted inside collars, the accelerometers monitor and record fine-scale movements of baboons along the x- (yellow), y- (blue), and z-axes (red). An algorithm then assesses the amount of movement in the three axes within a given time period, and classifies the behavior during that period as sleep (XX shading) or waking (YY shading). To confirm that the algorithm’s classification of sleep and waking is correct, baboons are also observed in their sleep site using infrared video recordings (inset). The method makes it possible to monitor the sleep of an entire group of wild baboons simultaneously and continuously. By doing so, the study finds that animals in the wild face ecological and social demands that can disrupt sleep homeostasis. Credit Mike Costelloe for Max Planck Institute of Animal Behavior Usage Restrictions Use of images is limited to editorial coverage of scientific topics relating to the activities of the Max Planck Society. Any kind of commercial use (including, in particular, the exploitation of images by means of sale or incorporation in image databases or image catalogues) as well as any promotional use/use for merchandise purposes, disclosure to third parties or granting of related rights to third parties is expressly not permitted. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.