Sleeping under the risk of predation

Lima, Steven L.; Rattenborg, Niels Christian; Lesku, John A.; Amlaner, Charles J.

doi:10.1016/j.anbehav.2005.01.008

Cited by 287 publications

(311 citation statements)

References 87 publications

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“…In addition, vulnerable grazing ungulates, such as antelopes, tend to sleep in herds, in which there are always some animals (sentinels) that are not asleep. 258 Strikingly, the NREM sleep in fur seals can be of two kinds. On land, seals exhibit, most of the time, a bilaterally symmetrical slow wave (BSW) sleep, similar to NREM sleep in terrestrial mammals.…”

Section: Suppression Of Sleep and Unihemispheric Sleepmentioning

confidence: 99%

“…Among terrestrial animals, only birds exhibit aspects of unihemispheric sleep, but not as pronounced as in cetaceans. 24,258 The USW sleep has evolved in marine mammals presumably because it is particularly adaptive in aquatic settings, as the terrestrial environment can provide an animal with a measure of protection during sleep, for example, in burrows and trees. In addition, vulnerable grazing ungulates, such as antelopes, tend to sleep in herds, in which there are always some animals (sentinels) that are not asleep.…”

Section: Suppression Of Sleep and Unihemispheric Sleepmentioning

confidence: 99%

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Augmented generation of protein fragments during wakefulness as the molecular cause of sleep: a hypothesis

Varshavsky

2012

Protein Science

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Despite extensive understanding of sleep regulation, the molecular-level cause and function of sleep are unknown. I suggest that they originate in individual neurons and stem from increased production of protein fragments during wakefulness. These fragments are transient parts of protein complexes in which the fragments were generated. Neuronal Ca 21 fluxes are higher during wakefulness than during sleep. Subunits of transmembrane channels and other proteins are cleaved by Ca 21 -activated calpains and by other nonprocessive proteases, including caspases and secretases. In the proposed concept, termed the fragment generation (FG) hypothesis, sleep is a state during which the production of fragments is decreased (owing to lower Ca 21 transients) while fragment-destroying pathways are upregulated. These changes facilitate the elimination of fragments and the remodeling of protein complexes in which the fragments resided. The FG hypothesis posits that a proteolytic cleavage, which produces two fragments, can have both deleterious effects and fitness-increasing functions. This (previously not considered) dichotomy can explain both the conservation of cleavage sites in proteins and the evolutionary persistence of sleep, because sleep would counteract deleterious aspects of protein fragments. The FG hypothesis leads to new explanations of sleep phenomena, including a longer sleep after sleep deprivation. Studies in the 1970s showed that ethanol-induced sleep in mice can be strikingly prolonged by intracerebroventricular injections of either Ca 21 alone or Ca 21 and its ionophore (Erickson et al., Science 1978;199:1219-1221 Harris, Pharmacol Biochem Behav 1979;10:527-534; Erickson et al., Pharmacol Biochem Behav 1980;12:651-656). These results, which were never interpreted in connection to protein fragments or the function of sleep, may be accounted for by the FG hypothesis about molecular causation of sleep.

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Section: Suppression Of Sleep and Unihemispheric Sleepmentioning

confidence: 99%

Section: Suppression Of Sleep and Unihemispheric Sleepmentioning

confidence: 99%

Augmented generation of protein fragments during wakefulness as the molecular cause of sleep: a hypothesis

Varshavsky

2012

Protein Science

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“…Why would an animal spend time sleeping when this entails sacrificing opportunities to find mates, resources, or invest in offspring? The costs of sleep might also have more immediate negative effects on survival, for example when a sleeping animal is more at risk of predation (Lima et al 2005;Lima & Rattenborg 2007). Among mammals, the risk of predation at the sleep site varies remarkably.…”

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confidence: 99%

“…Our investigation builds on suggestions that predation can influence the timing of prey sleep throughout the 24-hour cycle (Capellini et al 2008a), possibly in relation to the availability of alternative prey for predators and predator search behaviour (e.g. Lima et al 2005). Based on comparative studies in mammals, it appears that predation influences sleep patterns, at least in terms of sleep durations (Allison and Cicchetti 1976;Berger & Phillips 1995;Lesku et al 2006;Capellini et al 2008a).…”

mentioning

confidence: 99%

“…Here, our goal is to sharpen our intuition about the role of predation in the timing of sleep, while also using the model to search for new insights and predictions for future tests. Our model is grounded in tradeoffs among fitness-enhancing tasks, one of which involves the benefits of sleep, and in predator and prey behaviour over the daily cycle as a dynamic, competitive game (e.g., Kotler et al 2002;Lima et al 2005). The model we developed is individual based, meaning that we simulate local interactions at the level of individual agents (Grimm & Railsback 2005), and also evolutionary, in that the agents use evolutionary algorithms to solve ecological challenges that we designed.…”

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confidence: 99%

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