How do mice cope with a lack of food? - briefly
Mice respond to starvation by reducing basal metabolic rate, entering brief torpor, and mobilizing fat reserves for energy. Simultaneously, they intensify foraging, improve food‑search efficiency, and hoard any discovered nutrients to prolong survival.
How do mice cope with a lack of food? - in detail
Mice survive periods without adequate nutrition through a coordinated set of physiological and behavioral strategies. When energy intake declines, they immediately adjust metabolic rate, hormone secretion, and activity patterns to preserve vital functions.
The primary responses include:
- Metabolic suppression – basal metabolic rate drops by 10‑30 %, reducing heat production and oxygen consumption. Cellular pathways shift toward fatty‑acid oxidation, and glycogen stores in the liver are mobilized early.
- Hormonal modulation – leptin levels fall, signaling energy deficit; ghrelin rises, stimulating appetite. Corticosterone increases, promoting gluconeogenesis and protein catabolism.
- Body‑composition changes – adipose tissue is depleted, providing long‑chain fatty acids for peripheral tissues. Muscle protein is gradually broken down to supply amino acids for essential processes.
- Thermoregulatory adjustments – peripheral vasoconstriction limits heat loss; in extreme scarcity, mice can enter torpor, a short‑term hypothermic state that conserves up to 70 % of energy expenditure.
- Behavioral shifts – locomotor activity declines, especially during the light phase. Foraging effort intensifies during the dark cycle, with increased scent‑marking and exploratory behavior to locate hidden food sources.
- Social dynamics – in group settings, dominant individuals may monopolize limited resources, while subordinates reduce activity and may share nest warmth to offset individual energy loss.
- Gut microbiome adaptation – bacterial populations favor species capable of fermenting complex polysaccharides, enhancing extraction of residual nutrients from low‑quality food remnants.
These mechanisms operate simultaneously, allowing mice to endure several days of starvation before irreversible damage occurs. Recovery after refeeding involves rapid restoration of glycogen stores, normalization of hormone levels, and reactivation of normal activity cycles.