Document Detail


Behavioral sleep in the walrus.
MedLine Citation:
PMID:  19428620     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In this study we examined behavioral sleep in the walrus, the only living species of the family Odobenidae. The behavior of four 1.5-2-year-old captive walruses was videotaped continuously for 7-17 days and scored in 1-min epochs. When walruses had access to water and land, behavioral sleep, the combined amount of quiet and rapid eye movement (REM) sleep, occupied on average 17+/-4% of 24 h (n=4) with the majority of sleep occurring on land. All walruses alternated periods of almost continuous swimming lasting for 40-84 h with periods of rest on land lasting for 2-19 h. When in water they were predominantly awake (88-99% of the time). On land walruses were asleep on average 40-74% of the time. The total sleep time varied between 0 and 60% of 24h with the daily amount of REM sleep ranging from 0 to 5% of 24 h. In water, walruses slept while floating at the surface, lying on the bottom or standing and leaning against the pool wall. REM sleep in water occurred in all positions. On land the breathing pattern was regular during quiet sleep (most pauses were <30s) and arrhythmic in REM sleep (apneas lasted up to 160 s). While in water the irregularity of breathing further increased (apneas were >4 min) and all REM sleep episodes occurred during a single apnea. Data indicate that the pattern of sleep and breathing in walruses is similar to the Otariidae seals while on land and the Phocidae seals while in water.
Authors:
Julia P Pryaslova; Oleg I Lyamin; Jerome M Siegel; Lev M Mukhametov
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2009-02-02
Journal Detail:
Title:  Behavioural brain research     Volume:  201     ISSN:  1872-7549     ISO Abbreviation:  Behav. Brain Res.     Publication Date:  2009 Jul 
Date Detail:
Created Date:  2009-05-11     Completed Date:  2009-08-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8004872     Medline TA:  Behav Brain Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  80-7     Citation Subset:  IM    
Affiliation:
Utrish Dolphinarium Ltd., 33 Leninsky Prospect, Moscow 119071, Russia.
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MeSH Terms
Descriptor/Qualifier:
Animals
Environment
Female
Respiration
Sleep*
Sleep Apnea Syndromes / psychology
Sleep, REM
Swimming / psychology
Temperature
Time Factors
Video Recording
Walruses / psychology*
Water
Chemical
Reg. No./Substance:
7732-18-5/Water

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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