Question: what is the difference between the medulla of human and animal hairs?
Answer: - Medulla in a human is smaller (medullary index of less than one-third); and medulla in animals is very thick (medullary index of one-half or greater). - Cuticle in humans is imbricated; and the cuticle in animals is coronal or spinous. - Pigmentation in animal hair is denser than human hair.