The use of short tandem repeats (STRs) for the identification of animals has developed alongside similar STR applications for humans. Population studies, kinship analysis, paternity testing, and unique identification have been applied to humans and many other animals. The field of forensic science has adapted this information extensively in the prosecution of suspected criminals with great success. The power of human DNA testing is demonstrated routinely by the convictions and exonerations of individuals. We discuss how the use of nonhuman DNA testing is beginning to find a place in the prosecution of individuals. Animal evidence can be an important element in a case when used to establish an association between a crime scene and a suspect or in crimes involving a specific animal. Although the testing of animal evidence may be routine, its use in court is far less common. As the presentation of animal evidence in court increases, appropriate standards and guidelines must be applied to assure the admissibility of the DNA testing results in court. This requires rigorous validation of precision and accuracy, allele heritability and independence, accurate sampling, evidence handling, and appropriate statistical evaluation of the results before the criminal courts will accept and apply the power of DNA testing in cases involving animals.