What's the best reason to neuter your male dog? To ensure that he doesn't sire an unwanted litter of puppies. If health issues or other concerns make the surgery a no-go, however, there are other considerations as well. Here are three of the most noticeable differences between intact and neutered male dogs. 

Marking Behavior

Marking, or leaving a small amount of urine behind, is natural canine behavior — but it's much more pronounced in unneutered male dogs. The act is usually stimulated by the introduction of an unfamiliar object, especially one that already carries the scent of another animal. Vertical objects are the likeliest targets, which is why you'll often see dogs lifting their legs against lampposts, mailboxes, and fire hydrants.

While spayed and neutered dogs (even females) will sometimes engage in this behavior, studies have shown that getting the dog "fixed" can reduce marking incidents, especially in the house. In fact, as many as 80% of neutered male dogs will stop marking altogether. If you choose to leave your dog intact, it's a good idea to keep a healthy supply of enzyme cleaner on hand. 

Aggressive Behavior

An even more unfortunate side effect of keeping your dog intact is the likelihood that he'll spend more time fighting other dogs (or trying to, at least). Most dog bite incidents involve male dogs, and the majority of those are found to be intact. If your dog hasn't been neutered, he should be kept on a leash or confined to a fenced-in area whenever he's outside. On trips to the dog park, keep a close eye on his interactions with other dogs, and be prepared to remove him if he exhibits signs of aggression. 

Roaming Behavior

Intact male dogs can recognize the scent of a female in heat from several feet away, but most of them won't hang around and wait for one to get that close. They're more likely to roam the neighborhood or even the entire town, marking every spot they can manage and possibly engaging in territorial fights with other nearby males. This is yet another reason to keep your intact male dog confined or on a leash at all times.

Of course, it should be noted that hormones aren't the only things that might entice a dog to wander beyond the friendly confines of his home turf. A dog that's bored or lonely, or who doesn't get enough exercise, may feel the need to explore in the hope of finding companionship or excitement somewhere down the road. Whether your dog is intact or neutered, be sure to give him plenty of exercise and attention so that he won't be so tempted to seek his fortunes elsewhere.

If, for whatever reason, you've opted to keep your male dog intact, he'll require a bit more supervision than his neutered counterparts — especially when he's in the company of other dogs. As with any animal companion, though, you're bound to make whatever adjustments are necessary to ensure that your furry pal has the best life possible.