How many hours do rats sleep and at what times? - briefly
Rats usually sleep 12–15 hours per day, concentrating their rest during the light phase and becoming active in the dark phase. Their sleep consists of multiple short bouts of REM and non‑REM sleep spread throughout this resting period.
How many hours do rats sleep and at what times? - in detail
Rats are polyphasic sleepers, dividing rest into several episodes throughout a 24‑hour cycle. Laboratory observations of adult Norway rats (Rattus norvegicus) indicate a total daily sleep amount of approximately 12 to 14 hours. This sleep is split between rapid eye movement (REM) and non‑REM stages, with non‑REM constituting roughly 80 % of the time.
Typical distribution of sleep episodes:
-
Light phase (subjective day):
• 3 to 5 short bouts, each lasting 10–30 minutes.
• Occur primarily during the first half of the light period. -
Dark phase (subjective night):
• 4 to 6 longer bouts, each lasting 30–90 minutes.
• Concentrated in the early and late portions of the dark period, with a brief decline in the middle of the night.
The pattern reflects the animal’s crepuscular activity: rats are most active during the dark interval, interspersed with brief naps, while the light interval is dominated by longer, consolidated sleep. Environmental factors such as cage enrichment, temperature, and feeding schedule can shift the timing and length of individual bouts, but the overall daily total remains within the 12–14 hour range.