Open AccessCharacteristics of Sleep–Wakefulness Cycle and Circadian Activity in the Lesser Mouse-Deer (Tragulus kanchil)
Author(s) -
Oleg I. Lyamin,
Jerome M. Siegel,
R. V. Evsigneev,
E. A. Nazarenko,
В. В. Рожнов
Publication year - 2021
Publication title -
doklady biological sciences/doklady. biological sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.26
H-Index - 16
eISSN - 1608-3105
pISSN - 0012-4966
DOI - 10.1134/s0012496621050069
Subject(s) - circadian rhythm , wakefulness , sleep (system call) , biology , slow wave sleep , zoology , physiology , endocrinology , neuroscience , electroencephalography , computer science , operating system
The pattern of sleep and circadian activity of the lesser mouse-deer (Tragulus kanchil) that is the smallest (body mass between 1.5 and 2.2 kg) representative of the basal group (Tragulidae) of even-toed ungulates which evolved 40-50 Ma were studied. In naturalistic conditions, a total of 30 days of full-day video of the animal behavior and 15 days of 24-h polysomnographic data were collected in 6 animals. The mouse-deer were active less than 20% of 24 h and were quiescent during 60-80% of the remaining time. Slow wave sleep (SWS) accounted for on average 49.7 ± 3.7% of 24 h and paradoxical (rapid eye movement, REM) sleep accounted for 1.7 ± 0.3% of 24 h. During the majority of SWS (87.0 ± 4.4%) the eyes were open. The most of SWS and REM sleep occurred during the daytime hours (9 a.m. to 4 p.m.) and in the first half of the night (8 p.m. to 2 a.m.); the animals were most active during twilight hours (4-6 a.m. and 6-7 p.m.). We suggest that the main features of sleep in the mouse-deer are largely determined by ecological factors, including environmental temperature and predation, as well as the size and physiology of the mouse-deer.