1. Characteristics of Sleep–Wakefulness Cycle and Circadian Activity in the Lesser Mouse-Deer (Tragulus kanchil)
- Author
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Lyamin, OI, Siegel, JM, Evsigneev, RV, Nazarenko, EA, and Rozhnov, VV
- Subjects
Zoology ,Biological Sciences ,Behavioral and Social Science ,Sleep Research ,Neurosciences ,Basic Behavioral and Social Science ,Animals ,Circadian Rhythm ,Deer ,Electroencephalography ,Mice ,Sleep ,Sleep Stages ,Sleep ,REM ,Wakefulness ,REM sleep ,Tragulidae ,Tragulus kanchil ,circadian activity ,ecology ,evolution ,sleep ,slow wave sleep ,the lesser mouse-deer ,ungulates ,Biochemistry & Molecular Biology - Abstract
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.
- Published
- 2021