What type of identification is not acceptable for dogs or cats at acquisition?

Distinctive color markings are not an acceptable form of identification for dogs or cats at acquisition due to their inherent variability and subjectivity. Unlike other forms of identification, such as tattoos or tags, color markings can change due to various factors like fading over time or being misidentified due to similarities in appearance among different animals. This lack of reliability makes color markings insufficient for ensuring accurate and consistent identification of the animals.

In contrast, a tattoo on the hairless area of the ear, a tag on a collar around the animal's neck, and a tag on a collar affixed to a cat's primary enclosure provide more consistent and verifiable means of identifying the animals. These methods help ensure that each animal can be accurately tracked and managed throughout the research or care process, which is critical for compliance with regulatory requirements and the ethical treatment of animals in research.