Final answer:
The hair shaft, consisting of the cuticle, cortex, and medulla, is examined to differentiate human from animal hair; imbricate cuticle scales and certain medulla patterns, like a continuous pattern, are typically exclusive to animals.
Step-by-step explanation:
When trying to distinguish between human and animal hair, experts examine the hair shaft, which consists of three parts: the cuticle, cortex, and medulla. The type of cuticle scales found exclusively in animals are imbricate scales, which overlap like roof shingles and are not typically found in human hair.
Regarding medulla patterns, animals may have continuous, interrupted, fragmented, or absent medulla patterns, whereas human hair usually has a fragmented or absent medulla. Humans do not typically present with a continuous medulla, which is more commonly seen in the hair of many animal species. Forensic scientists use these differences in structure and pattern to help identify the species from which a hair sample originated.