Why doesn't a mouse run away? - briefly
A mouse may stay still when physically restrained, stunned, or when a predator’s proximity suppresses its flight response. In controlled environments, conditioning can further diminish the instinct to flee.
Why doesn't a mouse run away? - in detail
Mice often remain motionless or continue moving forward despite the presence of potential predators. Several physiological and behavioral mechanisms explain this apparent lack of escape.
- Sensory processing prioritises immediate threats; when a predator is detected, the mouse’s brain triggers a rapid assessment that can result in freezing rather than fleeing. Freezing reduces movement cues that predators use for detection.
- Evolutionary pressure favours energy conservation; unnecessary sprinting depletes glycogen stores, which are critical for later escape attempts. Consequently, the animal reserves high‑intensity locomotion for situations where escape is unequivocally possible.
- Neural circuitry involving the amygdala and periaqueductal gray mediates defensive responses. Depending on stimulus intensity, the circuit may select a “tonic immobility” pattern over a “flight” pattern.
- Habitat complexity influences behavior; in dense cover, rapid movement increases the risk of collision with obstacles, so the mouse may opt for cautious navigation rather than a direct dash.
Additional factors affect the decision not to run:
- Predator type: aerial predators often elicit a different response than ground predators, with some mice relying on camouflage rather than speed.
- Previous experience: individuals that have survived encounters by staying still are more likely to repeat the strategy.
- Physiological state: low body temperature or illness can impair motor function, limiting the ability to generate a swift escape.
Understanding these mechanisms clarifies why a mouse may not immediately retreat when threatened, favouring strategies that enhance survival under specific ecological conditions.