When do house mice sleep? - briefly
House mice are primarily nocturnal, resting throughout most of the daylight period and sleeping 12–14 hours per day. Their activity peaks during the night, especially in the early evening.
When do house mice sleep? - in detail
House mice are predominantly nocturnal. Their activity rises shortly after lights turn off and declines when illumination resumes. During the light phase they spend the majority of time asleep, interspersed with brief periods of wakefulness for grooming or feeding.
Total daily sleep amounts range from 12 to 14 hours. Sleep is polyphasic, consisting of multiple episodes lasting 5 to 30 minutes each. A typical pattern includes:
- Several long bouts (30–60 minutes) in the early daylight hours.
- Numerous short naps (5–15 minutes) scattered throughout the day.
- A brief resurgence of activity at dusk, followed by another extended sleep period after nightfall.
Electrophysiological recordings distinguish two main stages:
- Non‑rapid eye movement (NREM) sleep, which occupies roughly 70 % of total sleep time. Nslow waves dominate, indicating deep restorative sleep.
- Rapid eye movement (REM) sleep, accounting for about 30 % of sleep. REM episodes are short (1–3 minutes) and occur primarily toward the end of each sleep bout.
Environmental cues strongly influence the schedule. Constant darkness shifts activity to a free‑running rhythm, extending wake periods into the subjective day. Light pulses during the night suppress activity and trigger immediate sleep onset. Temperature variations affect bout length: cooler ambient conditions lengthen sleep episodes, while warmth shortens them.
Age and physiological state modify the pattern. Juvenile mice exhibit higher total sleep time (up to 16 hours) and longer REM periods. Pregnant or lactating females increase daytime sleep to allocate energy for reproduction. Laboratory strains may show reduced variability compared with wild counterparts, which adjust sleep timing to predator risk and food availability.
In summary, house mice allocate most of the light period to sleep, breaking it into many short episodes that together total over half a day. Their sleep architecture includes predominant NREM sleep with intermittent brief REM phases, both modulated by light, temperature, age, and reproductive status.