Which approach should be used to assess pain and distress in mice?

• A. Rely solely on vocalizations
• B. Use a combination of behavioral and physiological indicators
• C. Wait for obvious injury before assessing
• D. Use only body weight change

Answer: (B)

Assessing pain and distress effectively requires looking at multiple signs rather than trusting a single cue. Pain and distress can be subtle in mice, and individual animals may not vocalize or show obvious injury even when they are uncomfortable. By using a combination of behavioral indicators—such as changes in activity or locomotion, posture, gait, grooming, nesting, facial expressions (like those captured by the Mouse Grimace Scale), and reduced exploration or social interaction—and physiological indicators—such as changes in heart rate, respiration, body temperature, food and water intake, and weight trend—you gain a more sensitive and timely picture of how the animal is feeling. Relying only on vocalizations, waiting for obvious injury, or using body weight change alone can miss early distress or analgesia needs. The integrated approach supports earlier humane interventions and better welfare, which also helps maintain the integrity of experimental data.