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6 - Primate sleep in phylogenetic perspective
- Edited by Patrick McNamara, Boston University, Robert A. Barton, University of Durham, Charles L. Nunn
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- Book:
- Evolution of Sleep
- Published online:
- 10 March 2010
- Print publication:
- 12 October 2009, pp 123-144
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Summary
Introduction
The primates comprise a diverse group of eutherian mammals, with between some 200 and 400 species, depending on the taxonomic authority consulted (e.g., Corbet & Hill, 1991; Wilson & Reeder, 2005). Most of these species dwell in tropical forests, but primates also thrive in many other habitats, including savannas, mountainous forests of China and Japan, and even some urban areas. Living primates are divided into two groups, the strepsirrhines (lemurs and lorises) and the haplorrhines (monkeys, apes, and tarsiers). Strepsirrhines include mostly arboreal species and retain several ancestral characteristics, including greater reliance on smell and (in most species) a dental comb that is used for grooming. Most are nocturnal, but some have, in parallel with most haplorrhines, evolved a diurnal niche. They are found only in the Old World tropics. Haplorrhines are more widely distributed geographically, being found in both the New and Old Worlds. They include two groups, the platyrrhines and the catarrhines. Platyrrhines are monkeys native to the New World. Catarrhines include both Old World monkeys and apes. With the exception of owl monkeys in the genus Aotus, all monkeys and apes are active during the day (i.e., diurnal), and most live in bisexual social groups that vary in size from 2 to well over 100 adults (Smuts, Cheney, Seyfarth, et al., 1987).
Nonhuman primates are among the best-studied of mammals, in large part because of their close phylogenetic relatedness to humans.
1 - Ecological constraints on mammalian sleep architecture
- Edited by Patrick McNamara, Boston University, Robert A. Barton, University of Durham, Charles L. Nunn
-
- Book:
- Evolution of Sleep
- Published online:
- 10 March 2010
- Print publication:
- 12 October 2009, pp 12-33
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Summary
Introduction: sleep and ecology
All mammals so far studied experience some form of sleep. When mammals are sleep-deprived, they generally attempt to regain the lost sleep by exhibiting a “sleep rebound,” suggesting that sleep serves important functions that cannot be neglected (Siegel, 2008; Zepelin, 1989; Zepelin, Siegel, & Tobler, 2005). When sleep deprivation is enforced on individuals, it is accompanied by impaired physiological functions and a deterioration of cognitive performance (Kushida, 2004; Rechtschaffen, 1998; Rechtschaffen & Bergmann, 2002). In the rat, prolonged sleep deprivation ultimately results in death (Kushida, 2004; Rechtschaffen & Bergmann, 2002). Together, these observations suggest that sleep is a fundamental requirement for mammalian life, and much research has focused on identifying the physiological benefits that sleep provides (Horne, 1988; Kushida, 2004).
Are there also costs associated with sleep? If so, what are the selective pressures that constrain the amount of time that individuals can devote to sleep? Sleep is probably associated with “opportunity costs” because sleeping animals cannot pursue other fitness-enhancing activities, such as locating food, maintaining social bonds, or finding mates. Sleeping animals may also pay direct costs. For example, sleep is a state of reduced consciousness, and thus sleeping individuals are less able to detect and escape from approaching predators (Allison & Cicchetti, 1976; Lima, Rattenborg, Lesku, et al., 2005). These ecological factors are likely to be important constraints on sleep durations and may also affect how sleep is organized over the daily cycle.