The wolf equivalant to our fingerprint is a pair of scent glands located at the base of their tail. These secrete a scent which is different in every wolf. Wolves also use smell for marking out borders and paths in their territory. They mark with urine, excrement and digging. Their eyesight is superior and an excellent aid in hunting.
Eye color is another frequently debated topic.
Wolf eye color is brown, ranging from a deep chocolate brown to a striking yellow color such as that seen in the picture above. The wolf's superior hearing is used for hunting, communication and all other aspects of life.