Half-awake to the risk of predation

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

doi:10.1038/17037

Cited by 182 publications

(135 citation statements)

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“…Importantly, birds have the capacity to switch between BSWS and ASWS in response to changing ecological demands. Mallards (Anas platyrhynchos) sleeping in a group on land (figure 5b) switch from BSWS when safely flanked by other birds to ASWS when positioned at the edge of the group [5]. During ASWS at the edge, mallards direct the open eye away from the other birds, as if watching for approaching threats (figure 5c).…”

Section: How Might Birds Sleep In Flight?mentioning

confidence: 99%

“…Mallards sleeping at the edge of a group on land direct the open eye away from other birds, apparently to keep an eye out for approaching predators [5]. However, frigatebirds have no aerial predators.…”

Section: Sleep In Flying Frigatebirdsmentioning

confidence: 99%

“…In laboratory studies, this 'first night effect' is so prominent that data from the first night is usually ignored. However, based on the observation that mallards shift to sleeping asymmetrically when exposed to increased predation risk [5], Tamaki and co-workers [101] wondered whether a similar phenomenon might account for the first night effect in humans. Although we do not engage in unihemispheric sleep, the researchers discovered something similar.…”

Section: General Implicationsmentioning

confidence: 99%

“…ASWS can be further categorized as unihemispheric SWS (USWS) when the asymmetry is particularly pronounced [8]. During ASWS, including USWS, the eye opposite to the hemisphere that is sleeping more deeply is usually closed; whereas the other eye is usually open [5,62,83] (figure 5a). Importantly, birds have the capacity to switch between BSWS and ASWS in response to changing ecological demands.…”

Section: How Might Birds Sleep In Flight?mentioning

confidence: 99%

“…Moreover, an explanation for how birds could (theoretically) sleep in flight was provided by the discovery that dolphins can swim while sleeping with only half their brain at a time (i.e. unihemispherically) [4], and our subsequent discovery that birds on land can switch from sleeping with both halves simultaneously to sleeping with only one at a time in response to increased ecological demands for wakefulness [5]. By keeping one half of their brain awake and the corresponding eye open, flying birds could maintain aerodynamic control while watching where they are going.…”

Section: Introductionmentioning

confidence: 99%

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Sleeping on the wing

Rattenborg¹

2017

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Wakefulness enables animals to interface adaptively with the environment. Paradoxically, in insects to humans, the efficacy of wakefulness depends on daily sleep, a mysterious, usually quiescent state of reduced environmental awareness. However, several birds fly non-stop for days, weeks or months without landing, questioning whether and how they sleep. It is commonly assumed that such birds sleep with one cerebral hemisphere at a time (i.e. unihemispherically) and with only the corresponding eye closed, as observed in swimming dolphins. However, the discovery that birds on land can perform adaptively despite sleeping very little raised the possibility that birds forgo sleep during long flights. In the first study to measure the brain state of birds during long flights, great frigatebirds ( Fregata minor ) slept, but only during soaring and gliding flight. Although sleep was more unihemispheric in flight than on land, sleep also occurred with both brain hemispheres, indicating that having at least one hemisphere awake is not required to maintain the aerodynamic control of flight. Nonetheless, soaring frigatebirds appeared to use unihemispheric sleep to watch where they were going while circling in rising air currents. Despite being able to engage in all types of sleep in flight, the birds only slept for 0.7 h d −1 during flights lasting up to 10 days. By contrast, once back on land they slept 12.8 h d −1 . This suggests that the ecological demands for attention usually exceeded that afforded by sleeping unihemispherically. The ability to interface adaptively with the environment despite sleeping very little challenges commonly held views regarding sleep, and therefore serves as a powerful system for examining the functions of sleep and the consequences of its loss.

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Section: How Might Birds Sleep In Flight?mentioning

confidence: 99%

Section: Sleep In Flying Frigatebirdsmentioning

confidence: 99%

Section: General Implicationsmentioning

confidence: 99%

Section: How Might Birds Sleep In Flight?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sleeping on the wing

Rattenborg¹

2017

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The Evolution of Sleep: A Phylogenetic Approach

Lesku¹,

Rattenborg

Amlaner

2005

Sleep: A Comprehensive Handbook

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Do Chimpanzee Nests Serve an Anti‐Predatory Function?

Stewart

Pruetz

2013

American J Primatol

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Sleep is a vulnerable state for animals as it compromises the ability to detect predators. The evolution of shelter construction in the great apes may have been a solution to the trade-off between restorative sleep and predation-risk, which allowed a large bodied ape to sleep recumbent in a safe, comfortable spot. In this article we review the evidence of predator pressure on great apes and specifically investigate the potential influence of predation-risk on chimpanzee nesting behavior by comparing nests between chimpanzees living in a habitat of several potential predators (Issa, Ugalla, Tanzania) and a habitat relatively devoid of predators (Fongoli, Senegal). Chimpanzees in Issa did not nest more frequently in forest vegetation than chimpanzees in Fongoli although forest vegetation is expected to provide greater opportunity for escape from terrestrial predators. Nor do chimpanzees in Issa nest in larger groups or aggregate together more than Fongoli chimpanzees, as would be expected if larger groups provide protection from or greater detection of predators. Nests in Issa also did not appear to provide greater opportunities for escape than nests in Fongoli. Chimpanzees in Issa nested more frequently within the same tree as other community members, which may indicate that these chimpanzees nest in greater proximity than chimpanzees in Fongoli. Finally, Issa chimpanzees built their nests proportionately higher and more peripherally within trees. The selection of high and peripheral nesting locations within trees may make Issa chimpanzees inaccessible to potential predators. Many factors influence nest site selection in chimpanzees, of which danger from terrestrial predators is likely to be one.

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Half-awake to the risk of predation

Cited by 182 publications

References 3 publications

Sleeping on the wing

Sleeping on the wing

The Evolution of Sleep: A Phylogenetic Approach

Do Chimpanzee Nests Serve an Anti‐Predatory Function?

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