Which of the following is NOT a practical method of identifying mice?

• A. Leg band
• B. Ear tag
• C. Microchip
• D. Cage card

Answer: (A)

Identifying mice needs to be safe, durable, and easy to read without hindering movement or causing distress. A leg band is not practical for mice because their legs are very small and delicate; a band could constrict circulation, cause injury, or slip off easily, making identification unreliable and posing welfare concerns. In contrast, ear tags, when used correctly, provide a visible ID on the animal itself; microchips give a permanent, tamper-resistant identifier implanted under the skin; and cage cards convey the identity at the housing level without handling the mouse. Among these, the leg band stands out as not suitable for reliable, humane identification of mice.