Smell is an important factor in a wolflife so a good sense of smell is necessary for survival. The use it for tracking, hunting, communication and a lot more. Under good circumstances, a wolf could sense a prey 3 kilometers away. The wolf equivalent to our fingerprint is two glands of smell, one at the back and one at the rectum. The secrete from this two glands is different for every wolf.
Wolves also use smell for marking out borderlines and paths in their territory.
They mark with either urine, excrement or by digging in the ground. The distance between two marks is normally 100m, but the distance is smaller near borderlines to other wolves. The eyesight is terrific and a good aid in hunting etc.