Sleep in an Amazonian manatee,Trichechus inunguis

Mukhametov, L. M.; Lyamin, Oleg I.; Chetyrbok, I. S.; Vassilyev, Artem; Díaz, Roberto Ruiz

doi:10.1007/bf01923447

Cited by 39 publications

(24 citation statements)

References 1 publication

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“…Moss [1982] reported that wild African elephants, L. africana, sleep a total of 3-5 h at night, whereas captive Asian elephants, E. maximus, slept for approximately 4-6.5 h [Tobler, 1992;Wilson et al, 2006]. An electrophysiological study on an Amazonian manatee, T. inungius , revealed that this animal spent approximately 6.5 h (27%) in SWS and 14.4 min (1%) in REM sleep over a 24-hour period and that 25% of SWS was occupied by interhemispheric asymmetry [Mukhametov et al, 1992]; however, it must be noted that the TST reported was based on the study of a single animal and the recording of sleep was done directly after surgery, thus the TST obtained may not be representative of this species. As for the insectivoran-like afrotheres, TST in the tenrecs has been reported to be 15.6 h, with SWS contributing 13.26 h and REM 2.34 h [Campbell and Tobler, 1984;Elgar et al, 1988;Snyder et al, 1972].…”

Section: Comparison To Sleep In Other Afrotheria Xenarthra and Othermentioning

confidence: 99%

“…For members of the Afrotheria, sleep has been recorded behaviorally in captive Asian, Elephas maximus, and African elephants, Loxodonta africana, with TST in these animals being 4-6.5 and 3.3 h, respectively [Kurt, 1960;Tobler, 1992]. Electroencephalogram (EEG) recordings of a fully aquatic Amazonian manatee, Trichechus inungius, showed that this animal spent 6.48 h (27%) of the recorded time in SWS, which could be unihemispheric in nature, and 14.4 min (1%) in paradoxical or REM sleep [Mukhametov et al, 1992]; however, the study was performed on a single animal and the sleep recording commenced directly after surgery and lasted only a few days. Within the Hyracoidea, Snyder [1974] reports a TST of 4.9 h for Procavia johnstoni (rock hyrax) , 5.7 h for Heterohyrax brucei (bush hyrax) and 4.9 h for Dendrohyrax validus (tree hyrax); however, only an abstract has been published for the aforementioned study and detailed evidence has not been provided to support the reported data.…”

Section: Introductionmentioning

confidence: 99%

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Sleep in the Rock Hyrax, Procavia capensis

Gravett

Bhagwandin²,

Lyamin³

et al. 2012

Brain Behav Evol

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We investigated sleep in therock hyrax, Procavia capensis, a social mammal that typically lives in colonies on rocky outcrops throughout most parts of Southern Africa. The sleep of 5 wild-captured, adult rock hyraxes was recorded continuously for 72 h using telemetric relay of signals and allowing unimpeded movement. In addition to waking, slow wave sleep (SWS) and an unambiguous rapid eye movement (REM) state, a sleep state termed somnus innominatus (SI), characterized by low-voltage, high-frequency electroencephalogram, an electromyogram that stayed at the same amplitude as the preceding SWS episode and a mostly regular heart rate, were identified. If SI can be considered a form of low-voltage non-REM, the implication would be that the rock hyrax exhibits the lowest amount of REM recorded for any terrestrial mammal studied to date. Conversely, if SI is a form of REM sleep, it would lead to the classification of a novel subdivision of this state; however, further investigation would be required. The hyraxes spent on average 15.89 h (66.2%) of the time awake, 6.02 h (25.1%) in SWS, 43 min (3%) in SI and 6 min (0.4%) in REM. The unambiguous REM sleep amounts were on average less than 6 min/day. The most common state transition pathway in these animals was found to be wake → SWS → wake. No significant differences were noted with regard to total sleep time, number of episodes and episode duration for all states between the light and dark periods.Thus, prior classification of the rock hyrax as strongly diurnal does not appear to hold under controlled laboratory conditions.

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Section: Comparison To Sleep In Other Afrotheria Xenarthra and Othermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Sleep in the Rock Hyrax, Procavia capensis

Gravett

Bhagwandin²,

Lyamin³

et al. 2012

Brain Behav Evol

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“…In contrast to Cetaceans, the degree of IA is usually less pronounced in eared seals and least pronounced in birds. In Cetaceans, deep SWS virtually never occurs simultaneously in both hemispheres, whereas eared seals, manatees and birds frequently show deep SWS in both hemispheres [Ball et al, 1988;Lyamin and Chetyrbok, 1992;Mukhametov et al, 1992]. Although mammals and birds exhibit two types of sleep (i.e., SWS and rapid-eye-movement, REM, sleep), only SWS occurs unihemispherically.…”

Section: Introductionmentioning

confidence: 99%

Unilateral Eye Closure and Interhemispheric EEG Asymmetry during Sleep in the Pigeon (Columba livia)

Rattenborg

Amlaner

Lima³

2001

Brain Behav Evol

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Aquatic mammals (i.e., Cetaceans, eared seals and manatees) and birds show interhemispheric asymmetries (IA) in slow-wave sleep-related electroencephalographic (EEG) activity, suggesting that the depth of sleep differs between hemispheres. In birds, an association between unilateral eye closure and IA has been reported in five species from three orders (i.e., Galliformes, Charadriiformes, and Anseriformes). Moreover, unilateral eye closure has been observed during behaviorally defined sleep in 29 species from 13 avian orders, suggesting that birds in general display IA during sleep. Despite the apparent prevalence of unilateral eye closure and IA in birds, previous work did not detect IA in the pigeon, thereby challenging the conclusion that this is a general feature of birds. Using digital period amplitude analysis, an objective method for quantifying EEG power (a measure of wave amplitude) across different frequencies, we demonstrate that pigeons do, in fact, display an association between unilateral eye closure and IA. For a given hemisphere, standardized 2–4 Hz EEG power was greater when the contralateral eye was closed when compared to open. We also found that pigeons used the open eye during IA to monitor their environment. In addition, individual pigeons showed a bias for keeping one eye open more than the other. The direction (left vs. right) of this bias differed across birds, and appeared to be influenced by the structure of the surrounding environment. Finally, with the addition of pigeons (order Columbiformes), IA associated with unilateral eye closure has been recorded in four avian orders, suggesting that this form of sleep is widespread in birds.

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“…In addition, they noted that the [58] , though an earlier study by Shurley et al (in 1969) reported episodes of REM sleep in the pilot whale [59] . In all subsequent physiological studies, however, it was confirmed that REM sleep is absent from the Cetacea bottle nose dolphin [60] , black sea porpoise [61] , amazon river dolphin [62] and beluga whale [63] , while in the amazon manatee (Sirenia), only a few episodes of REM sleep were recorded [64] .…”

Section: Mukhametov and His Team (In 1975) Recorded Eeg Inmentioning

confidence: 95%

“…In fact, it has been suggested that sleep in fur seals defies the principle of homeostatic regulation, since no rebound of lost REM is seen when it returns to land after staying several weeks in water [42] . (dolphin and white whale: 0%; manatee: 1%) [64,65] . Semi- as disk-over water, multiple or single platform, and wiremesh grid platform in which water is used as the surrounding medium [66][67][68][69] .…”

Section: Do Aquatic Conditions Disfavor Rem Sleep Continuity?mentioning

confidence: 99%

Sleep alterations in mammals: Did aquatic conditions inhibit rapid eye movement sleep?

Madan

Jha

2012

Neurosci. Bull.

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Sleep has been studied widely in mammals and to some extent in other vertebrates. Higher vertebrates such as birds and mammals have evolved an inimitable rapid eye movement (REM) sleep state. During REM sleep, postural muscles become atonic and the temperature regulating machinery remains suspended. Although REM sleep is present in almost all the terrestrial mammals, the aquatic mammals have either radically reduced or completely eliminated REM sleep.Further, we found a significant negative correlation between REM sleep and the adaptation of the organism to live on land or in water. The amount of REM sleep is highest in terrestrial mammals, significantly reduced in semi-aquatic mammals and completely absent or negligible in aquatic mammals. The aquatic mammals are obligate swimmers and have to surface at regular intervals for air. Also, these animals live in thermally challenging environments, where the conductive heat loss is approximately ~90 times greater than air. Therefore, they have to be moving most of the time. As an adaptation, they have evolved unihemispheric sleep, during which they can rove as well as rest. A condition that immobilizes muscle activity and suspends the thermoregulatory machinery, as happens during REM sleep, is not suitable for these animals. It is possible that, in accord with Darwin's theory, aquatic mammals might have abolished REM sleep with time. In this review, we discuss the possibility of the intrinsic role of aquatic conditions in the elimination of REM sleep in the aquatic mammals.

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Sleep in an Amazonian manatee,Trichechus inunguis

Cited by 39 publications

References 1 publication

Sleep in the Rock Hyrax, <i>Procavia capensis</i>

Sleep in the Rock Hyrax, <i>Procavia capensis</i>

Unilateral Eye Closure and Interhemispheric EEG Asymmetry during Sleep in the Pigeon <i>(Columba livia)</i>

Sleep alterations in mammals: Did aquatic conditions inhibit rapid eye movement sleep?

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