How many hours do mice sleep per day? - briefly
Mice typically sleep between 12 and 14 hours each day. Their rest is polyphasic, consisting of several short episodes spread across the light‑dark cycle.
How many hours do mice sleep per day? - in detail
Mice typically rest for roughly 12–14 hours each 24‑hour period. Laboratory strains, maintained under controlled light‑dark cycles (12 h light, 12 h dark), often reach the upper end of this range, with some reports of 15 hours in highly sedentary conditions. Wild counterparts, exposed to predators and variable foraging demands, generally record slightly shorter sleep bouts, averaging 10–12 hours.
Sleep in rodents is polyphasic: several short episodes are distributed across both the light and dark phases. During the light phase, mice exhibit longer, consolidated periods of inactivity, while the dark phase includes brief naps interspersed with active foraging. The architecture comprises alternating non‑rapid eye movement (NREM) and rapid eye movement (REM) stages, each lasting only a few minutes before transitioning.
Key variables influencing daily sleep duration include:
- Strain genetics – Inbred lines such as C57BL/6J tend to sleep more than outbred strains.
- Age – Juvenile mice show up to 16 hours of sleep; this declines to about 10 hours in senescent individuals.
- Environmental lighting – Constant darkness or light shifts the timing and length of sleep bouts.
- Temperature – Ambient temperatures below thermoneutral range (30 °C) increase sleep time to conserve energy.
- Dietary composition – High‑fat diets can extend total sleep by 1–2 hours, likely due to metabolic effects.
- Health status – Infection, pain, or neurological lesions reduce both total sleep and REM proportion.
Electroencephalographic recordings confirm that mice spend approximately 50–60 % of their sleep time in NREM and 20–30 % in REM, with the remainder in transitional states. Sleep deprivation experiments demonstrate rapid rebound, with an increase of 150–200 % in total sleep time during the subsequent recovery period.
In summary, the average daily sleep allotment for mice lies between 10 and 15 hours, modulated by genetic background, age, environmental conditions, and physiological state.