How can one tell if a mouse is dead? - briefly
Absence of breathing and heartbeat, combined with no reaction to gentle touch or sound, indicates mortality. After a brief interval the body becomes rigid as rigor mortis sets in.
How can one tell if a mouse is dead? - in detail
When a rodent is found motionless, the first step is to assess physical cues that differentiate death from temporary inactivity.
Visual inspection should focus on the following indicators:
- Rigor mortis: stiffening of limbs and torso within a few hours after death.
- Lack of coloration: pallor or a grayish hue replaces the normal pinkish tone.
- Absence of eye movement: pupils remain dilated and unresponsive.
- No visible respiration: chest and abdomen show no rise and fall.
Tactile evaluation provides additional confirmation. A gentle press on the forearm or hind leg should reveal a firm, unyielding texture if rigor mortis is present; a living mouse retains a slight give.
Assessing reflexes clarifies the situation further. Apply a mild stimulus—such as a light touch to the whiskers, a gentle tap on the tail, or a brief puff of air. A living animal will exhibit a twitch, grooming motion, or vocalization; a deceased specimen will show no response.
If uncertainty persists, examine the nasal passages and mouth. A living mouse maintains a clear, moist mucous membrane, while a dead one often displays dried secretions and a collapsed airway.
In cases where decomposition may have begun, look for putrefactive signs: foul odor, bloating, and discoloration of internal organs upon dissection. These changes confirm mortality beyond doubt.
By systematically checking visual appearance, tissue firmness, reflexive behavior, and, when necessary, internal condition, one can reliably determine whether a mouse has ceased living.