Animal identification is a critical component of the necropsy procedure. Identification of animals (or group of animals) is important to ensure that accurate information on the health status of each submitted animal is obtained. To facilitate accurate identification of animals we would like to offer the following suggestions for marking the animals.

1. Animals of all coat colors may be marked on tails with different color permanent markers (Figure 1). A 2 mm band around the tail is preferable to prevent removal of mark by excessive grooming while in transit. It is best to use no more than 10 lines per animal. Avoid black markings on dark tailed mice; other colors such as blue, red and green work well for these mice.
   
   
   Figure 1
   
2. If sending 20 or more animals that are ear tagged, ear punched or toe clipped in the same box, consider identifying groups of 10 mice with a secondary marking system. For example groups can be designated with different colored stripes along the length of the tail (Figure 2). This will aid in identification of animals whose primary means of identification has been damaged, lost or is difficult to interpret. The latter is not uncommon with many ear notching schemes.
   
   
   Figure 2
   
   
3. In our experience, cardboard and plastic dividers are often not adequate at keeping animals separated during shipping. Occasionally the box may be damaged in shipping, allowing animals to move freely over or under dividers. Also, animals may chew through dividers. Therefore, it is beneficial to differentiate animals that are in the same box but separated by a divider by coat color or other markings.
   
4. Regardless of the marking system, please describe the method used to identify animals on the submission form.