Biology subjects

Samson, D. R.

Publications and source records attributed to Samson, D. R..

3 recordsLinked to original sources

bioRxiv2021

Enriched sleep environments lengthen lemur sleep duration

Characteristics of the sleep-site are thought to influence the quality and duration of primate sleep, yet only a handful of studies have investigated these links experimentally. Using actigraphy and infrared videography, we quantified sleep in four lemur species (Eulemur coronatus, Lemur catta, Propithecus coquereli, and Varecia rubra) under two different experimental conditions at the Duke Lemur Center (DLC) in Durham, NC, USA. Individuals from each species underwent three weeks of simultaneous testing to investigate the hypothesis that comfort level of the sleep-site influences sleep. We obtained baseline data on normal sleep, and then, in a pair-wise study design, we compared the daily sleep times of individuals in simultaneous experiments of sleep-site enrichment and sleep-site impoverishment. Over 163 24-hour periods from 8 individuals (2 of each species), we found strong evidence that enriched sleep-sites increased daily sleep times of lemurs, with an average increase of thirty-one minutes. The effect of sleep-site impoverishment was small and not statistically significant. We conclude that properties of a sleep-site enhancing softness or insulation, more than the factors of surface area or stability, influence lemur sleep, with implications regarding the importance of nest building in primate evolution and the welfare and management of captive lemurs.

animal behavior and cognition↗

bioRxiv2021

A brief report of sleep and circadian rhythm quotas in a population of dog owners in North Carolina, USA

ObjectivesTo characterize sleep and circadian rhythms of a sample population of healthy, dog-owning adults from North Carolina, USA. MethodsActigraphy was used to analyze sleep-wake patterns in forty-two dog owners from the Raleigh area in North Carolina. Sleep quotas, including sleep duration, efficiency, and fragmentation were measured alongside a Non-parametric Circadian Rhythms Analysis (NPCRA) to quantify strength, consistency, and fragmentation of rhythms. ResultsCompared to females, males demonstrated later sleep onset and sleep end (p<0.01), greater wake after sleep onset and sleep fragmentation (P<0.001), and lower sleep efficiency (p<0.001). The NPCRA revealed comparable relative amplitude (strength) and interdaily stability (consistency), yet less intra-daily variability (fragmentation), than previously reported post-industrial samples. ConclusionsThis study adds to the current data available on sleep and circadian rhythms in discrete human populations and highlights the need for more research characterizing cross-cultural sleep and circadian rhythmicity.

evolutionary biology↗

bioRxiv2020

A sleep epidemic or enlightenment? A Bayesian approach to test the sleep epidemic hypothesis shows foragers have short and fragmented sleep compared to large scale societies

Human sleep is linked with nearly every aspect of our health and wellbeing. The question whether and to what extent human sleep is in a state of evolutionary mismatch has gained recent attention from both clinical and biological science researchers. Here, I use a comparative Bayesian approach aimed at testing the sleep epidemic hypothesis - the idea that, due to labor demands and technological disruption, sleep-wake activity is negatively impacted in post-industrial, economically developed societies. In contrast to the expectations of the sleep epidemic hypothesis, when compared to both large and small-scale subsistence societies that rely on agriculture for subsistence, foragers were the shortest, least efficient sleeping group. Coupled with previous work demonstrating that foragers have stronger circadian rhythms compared to those sleeping in buffered environments, I present the sleep-rhythm trade-off hypothesis - that sleep duration, quality, and synchrony is driven by trade-offs between sleep security and comfort versus sleep site environmental exposure. One strategy to improve wellbeing of modern sleepers would be to focus on behavioral interventions that reduce desynchronizations of circadian rhythms, while holding the positive ground of safe, secure, and regulated sleep environments typical of economically developed societies.

evolutionary biology↗