Which of the following is NOT considered enrichment for laboratory mice?

• A. Food pellets.
• B. Nesting material.
• C. Shelter.
• D. Tunnels.

Answer: (A)

Environmental enrichment is about expanding the mouse’s opportunities to perform natural behaviors and engage its mind and body beyond basic care. Nesting material lets a mouse build a nest and regulate warmth, shelter provides a safe retreat and privacy, and tunnels invite exploration and physical activity. Food pellets, while essential for nutrition, do not by themselves add behavioral opportunities beyond eating; they are part of the standard diet. In enrichment, feeding can be made into foraging challenges or puzzle feeders to become enriching, but plain food pellets are not enrichment.