How long do mice live without food? - briefly
Mice can survive roughly two to four days without any food, provided they have access to water. Prolonged deprivation beyond this window results in swift physiological decline and death.
How long do mice live without food? - in detail
Mice can survive for a limited period when deprived of any caloric intake, but the exact duration varies with age, sex, strain, ambient temperature, and hydration status.
- Neonatal pups (under 2 weeks old) typically die within 24–48 hours because they lack sufficient energy reserves.
- Adult laboratory mice (8–12 weeks old) generally endure 3–5 days without food if water remains available. Mortality usually begins after the third day, with most individuals succumbing by the fifth.
- Older or larger individuals may persist slightly longer, sometimes up to 7 days, but physiological decline accelerates rapidly after day 4.
Key physiological mechanisms influencing survival include:
- Glycogen depletion: Liver glycogen stores are exhausted within 12–24 hours, forcing a shift to gluconeogenesis.
- Gluconeogenic substrates: After glycogen loss, protein catabolism supplies amino acids for glucose production; muscle wasting becomes evident.
- Ketogenesis: By the second day, hepatic ketone production rises, providing an alternative fuel for the brain and heart.
- Thermoregulation: In cold environments (below 20 °C) energy expenditure for heat production increases, shortening survival time.
- Hydration: Access to water markedly extends life; without water, death occurs within 24–48 hours regardless of food availability.
Experimental observations under controlled conditions (22 °C, 12 h light/dark cycle, ad libitum water) report median survival times of 4.2 days for C57BL/6J mice and 4.6 days for BALB/c mice. Stressors such as handling, isolation, or infection can reduce these values by 0.5–1 day.
In summary, adult mice typically survive three to five days without nourishment when water is present, with survival length modulated by physiological reserves, ambient temperature, and strain‑specific metabolic traits.