When trudging through the Arctic snow, polar bears leave a scent behind. Other bears sniffing them can follow this scent. Bears uses specific tracks so they can meet individuals they want to mate and uses it as well to avoid bears that might hurt them. Using the footprints left behind by a bear, other bears can figure out if it is a friend or not. During spring mating season, bears are out to track potential mates.
However, climate change seems to threaten this process according to researchers.