Sleep and nesting behavior in primates: A review

Abstract

Sleep is a universal behavior in vertebrate and invertebrate animals, suggesting it originated in the very first life forms. Given the vital function of sleep, sleeping patterns and sleep architecture follow dynamic and adaptive processes reflecting trade-offs to different selective pressures. Here, we review responses in sleep and sleep-related behavior to environmental constraints across primate species, focusing on the role of great ape nest building in hominid evolution. We summarize and synthesize major hypotheses explaining the proximate and ultimate functions of great ape nest building across all species and subspecies; we draw on 46 original studies published between 2000 and 2017. In addition, we integrate the most recent data brought together by researchers from a complementary range of disciplines in the frame of the symposium "Burning the midnight oil" held at the 26th Congress of the International Primatological Society, Chicago, August 2016, as well as some additional contributors, each of which is included as a "stand-alone" article in this "Primate Sleep" symposium set. In doing so, we present crucial factors to be considered in describing scenarios of human sleep evolution: (a) the implications of nest construction for sleep quality and cognition; (b) the tree-to-ground transition in early hominids; (c) the peculiarities of human sleep. We propose bridging disciplines such as neurobiology, endocrinology, medicine, and evolutionary ecology, so that future research may disentangle the major functions of sleep in human and nonhuman primates, namely its role in energy allocation, health, and cognition.

Deciding Where to Sleep: Spatial Levels of Nesting Selection in Chimpanzees (Pan troglodytes) Living in Savanna at Issa, Tanzania

“…Sleep is one of the vital behaviors in animals and the one that involves the highest risk of predation, making the decision of where to sleep essential for survival (Fruth et al 2018;Lima et al 2005;Mainwaring et al 2014;Reinhardt 2020). Primates show a great diversity of sleeping places.…”

“…Small apes use bare tree branches and parasitic plants on branches to sleep (Fan and Jiang 2008). Great apes build beds, or complex structures of vegetation (called nests) for sleeping, mostly in trees, but chimpanzees (Pan troglodytes) and gorillas (Gorilla gorilla) also build terrestrial nests and gorillas can sleep on the bare ground (Fruth and Hohmann 1996;Fruth et al 2018).…”

“…The most important function of a primate sleeping place is thought to be its safety from potential predators (Anderson 1984(Anderson , 1998. Primates select sleeping places that help to decrease predation risk, such as high trees, trees with dense foliage, steep cliffs, concealed nests, inaccessible trees, or tree holes (Anderson 1984(Anderson , 1998Brividoro et al 2019;Fruth et al 2018;Hamilton 1982;Kappeler 1998;Phoonjampa et al 2010). For example, golden-brown mouse lemurs (Microcebus ravelobensis) construct leaf nests more often during infant rearing when predator risk is higher than at other times (Thoren et al 2010).…”

“…Like the sleeping places of other primates, great ape nests are also proposed to function in predator avoidance, thermoregulation, comfort, and pathogen or pest avoidance (Anderson 1984;Fruth and Hohmann 1996;Fruth et al 2018;Goodall 1962;McGrew 1992McGrew , 2004. For example, arboreal sleeping serves to avoid ground predators.…”

Potential use of actigraphy to measure sleep in monkeys: comparison with behavioral analysis from videography

“…Likewise, sleep also plays a dominant role in NHP health, behavior, and ecology, and can exert a significant influence on daily activity schedules ( Anderson, 1998 , 2000 ; Qiu et al, 2019 ). Thus, NHPs are especially valuable for comparative studies on sleep, with tremendous potential to provide critical improvement in our understanding of human sleep and associated disorders ( Fruth et al, 2018 ; Nunn et al, 2010 ).…”