A Simple Technique for the Permanent Marking of Newborn Albino Rats

Abstract

Routine methods of marking rats cannot be used for identifying litter members at, or shortly after, birth, nor can they be effectively applied until a few weeks later. Injection of India ink under or into the palm of the forefoot or the sole of the rear foot of the newborn rat, however, provides a clearly discernible, permanent mark which permits litter members to be differentiated with ease. This method, the details of which are described, has been used successfully on some 3,000 newborn albino rats, many of which have been studied for 20 to 30 mo. or longer.