Animal identification

Animal identification is a crucial element in almost every experiment. The identification of an animal is the only link to very important data, like the genotype for instance. The need for genotyping leads to the requirement to identify very young mice, thus creating specific problems. Loss of identification during the selection process in breeding makes animals unusable for further experimentation or breeding or repetition of both identification and genotyping is needed. Such animals are therefore often eliminated. In addition to well established methods, some techniques are recently introduced where not yet all implications are considered. For example, implanting electronic transponders bears the risk of chronic tissue irritation with the potential to promote tumor formation. Another example is the method of digital microtattoo where the impact on anatomical structures of the digits is not yet investigated. Toe clipping is not allowed in certain geographical areas, whereas this is a standard method elsewhere; decisions are rarely scientifically based. Recommendation should be given for suitable methods according to experimental purposes for the identification of small rodents. It will allow researchers to make the best choice, considering aspects of animal’s anatomy, physiology and behavior as well as interference with research.