What is a typical lighting cycle used for normal colony maintenance?

What is a typical lighting cycle used for normal colony maintenance?

• A. 12:12 light to dark cycle
• B. 14:10 light to dark cycle
• C. 24 hour continuous light
• D. 6:18 light to dark

Answer: (A)

Regular, balanced light-dark cycles regulate circadian rhythms in most lab animal colonies, supporting normal activity, feeding, and reproduction. A 12 hours of light followed by 12 hours of darkness provides a standard photoperiod that mirrors natural day-night patterns, yielding predictable physiology and behavior essential for routine colony maintenance. Other options push the system out of balance: continuous light eliminates the dark period and can disrupt sleep, hormones, and breeding; a very short daylight period like 6:18 can reduce daytime activity and welfare; a longer photoperiod such as 14:10 is not the default for normal maintenance. So, the 12:12 cycle best supports consistent, healthy colony conditions.

Regular, balanced light-dark cycles regulate circadian rhythms in most lab animal colonies, supporting normal activity, feeding, and reproduction. A 12 hours of light followed by 12 hours of darkness provides a standard photoperiod that mirrors natural day-night patterns, yielding predictable physiology and behavior essential for routine colony maintenance.

Other options push the system out of balance: continuous light eliminates the dark period and can disrupt sleep, hormones, and breeding; a very short daylight period like 6:18 can reduce daytime activity and welfare; a longer photoperiod such as 14:10 is not the default for normal maintenance. So, the 12:12 cycle best supports consistent, healthy colony conditions.