What part of a dog is equivalent to human fingerprint?

There isn't a direct equivalent to human fingerprints in dogs. Dogs don't have the same type of unique, detailed patterns on their paws as humans do on their fingers.

While dog paws do have individual features, such as the size, shape, and arrangement of paw pads and the texture of their skin, these features aren't as consistent or as uniquely identifiable as fingerprints.

However, dogs do have unique noses, and the patterns on their noses are sometimes used for identification, much like fingerprints. The wet, bumpy surface of a dog's nose has a unique pattern of ridges and valleys, similar to a human fingerprint. This pattern is thought to be unique to each dog.

While it's not as common as using fingerprints, nose prints are increasingly used in areas like law enforcement and animal shelters for identification and tracking.