Which statement about lighting management contributes to mouse welfare?

• A. Circadian rhythm and welfare
• B. Rapid growth
• C. Increased aggression
• D. None of the above

Answer: (A)

Lighting management that supports circadian rhythms is central to mouse welfare. Mice are most active in darkness and rely on a regular light-dark cycle to regulate sleep, feeding, hormone balance, and immune function. When the photoperiod is consistent and transitions are not sudden, stress is reduced and normal physiology and behavior are better maintained, promoting overall well-being. Irregular or overly bright lighting can disrupt these rhythms, leading to poor sleep, metabolic imbalances, and increased stress—all of which negatively impact welfare. Growth rate isn’t directly controlled by lighting, and aggression is influenced by multiple factors beyond lighting. So the link between circadian rhythm and welfare best explains how lighting management supports mouse well-being.