Taking a nice, leisurely stroll with your pooch can turn into an all-out tug-of-war when you try to pull him away from a particularly interesting tree. Dogs' noses are up to 10,000 times more sensitive than yours, so they get easily distracted by scents at potty time.
Flipping Through the Phone Book
If you want to see who lives in your town, you once flipped through the phone book to look for familiar names. Dogs do much the same thing when they sniff around before obeying your "potty" command. Their noses can detect the scents of other dogs in the area, particularly if the dogs went to the bathroom there. Your pup can even tell the gender of the recent dogs in the area as well as what they had for dinner. In the wild, this sense helped them find packs that were well-fed.
Not only does your pooch smell around like crazy at your neighbor's mailbox, but he also lifts his leg briefly for some relief of his own. This is one way dogs show dominance -- by marking their territory. It's your dog's way of saying, "This is MY mailbox!" to other dogs after he smells their markings.
Wanna Go Out?
Dogs have an instinctual drive to make puppies, and they sniff for available dogs when they are looking for the right bathroom spot. A male dog smells for females who might be in heat -- it's not unusual for them to take off like a bullet in the direction they think the females went. Females in heat might also smell for available males, although they are unlikely to do much pursuing. They typically prefer to let the guys make the first move.
If you notice your pup munching madly on something while you're waiting on him to finish his business, don't be surprised. Dogs are constantly sniffing for items that are remotely edible, even if they aren't hungry. Your pooch might smell the extra tasty treat of day-old, discarded potato chips behind the tree and make a beeline for them, but it's best to keep your dog away from unknown food when it's potty time. The food could be rotten or contain toxins that can harm your pup.