Why Dogs Pee on Fire Hydrants

Why Dogs Pee on Fire Hydrants

Do you sometimes feel as if your dog stops to pee at every fire hydrant when you take him for a walk in your neighborhood? Dog walkers will tell you that most dogs, especially male dogs, try to pee on every fire hydrant they pass. You’ve most probably asked yourself whether all dogs do it and, if so, why.

There are various reasons why dogs prefer fire hydrants, including the placement and height of hydrants and, according to some, even the paint on the hydrant. Unlike many trees, fire hydrants have no branches that can get in the way, and fire hydrants are natural boundaries on every corner in cities and suburban areas to demarcate a dog’s territory.

To understand this phenomenon, we’ll have to determine why dogs pee on vertical objects, why fire hydrants are so popular, and whether it is limited to male dogs only.

Different Reasons for Peeing

When a dog urinates to relieve itself, it is not too bothered where and how it is done. For a female dog, squatting anywhere as soon as she is outside is normal. A male dog will simply lift his leg against the nearest object. It seems as if no other factors are taken into account. To understand more about this, read “Is My Dog Peeing for Attention?

However, dogs are motivated to relieve themselves for many reasons other than simply relieving themselves. As we outline below, these more ulterior motives play a role when the dog is relaxed and “patrolling” its environment.

To Mark Territory

The most important role of peeing on an object is to scent-mark and claim a specific territory. Scent-marking is an important form of communication within and across species. Animals in the wild use pee to scent mark, which is one of the characteristics still inherent in domestic dogs.

When your dog is peeing to mark its territory, it is advertising its availability to mates. The marking also gives warning signals to potential competitors. The marking is an ongoing process, as the signal decays due to rain, ultraviolet radiation, and bacterial decomposition. 

Thus, the territory has to be marked frequently. Observing free-ranging dogs, it has become clear that scent-marking is done more during rainy seasons (source).

It is not only intact male dogs that do scent-marking. Many neutered males, as well as some females — even spayed females — also mark. When a dog is marking, especially a female dog, the urine volume is usually small (source).

To Overmark

Overmarking occurs when your dog catches the scent of a neighbor dog on an object. Your dog will then purposefully pee over the area previously scented by the other dog to replace the scent with its own. In doing so, your dog communicates that it’s higher up in the pack order.

Male dogs overmark the urine of other males more frequently than they mark over females’ urine (source). Overmarking is used to show dominance and not so much to attract dogs of the other sex.

Why Pee on Vertical Objects?

With scent-marking, a dog conveys to his competitors or possible mates that he is around and that he is the largest dog in the neighborhood. The higher you can pee, the larger you are. And the larger you are, the more dominant you are.

This is one of the reasons you sometimes see very small dogs standing on their front legs to position themselves to pee as high up as possible on a vertical object.

To urinate as high as possible, your dog involuntarily looks for an object with height. Tree trunks, poles, fences, and hydrants are the most obvious targets.

During a research project in West Bengal, India, it was observed that male dogs more frequently did scent-marking than females. A vertical object to urinate against is more important for male dogs than for females. 

Peeing against vertical objects by lifting one leg is the normal way of marking for more than 95% of male dogs. By contrast, female dogs lifting their leg against a vertical object occurs in less than 25% (source).

It is so natural for a dog, especially a male dog, to pee against a vertical object that it is recommended by dog trainers that if your circumstances are of such a nature that you have to train your male dog to pee inside, you must put a vertical object in a suitable place. 

The advice is to then train the dog to pee only at this one dedicated place. Your male dog will more easily learn to urinate only in one place if there is a vertical object to lift his leg against (source).

Why Are Fire Hydrants Preferred?

With all this said, the question is still what makes the fire hydrant such a popular target for peeing and scent-marking, apart from being a vertical object?

Natural Territorial Boundary

In a suburban environment, a fire hydrant is generally available on every street corner. Your dog wants to mark the boundaries of its territory, and the hydrants offer the opportunity to mark a border. By marking all the hydrants around your street block, your dog is sending out the message that the area is its domain.

Scent Stays Longer

In comparison with a tree trunk, there is very little, if any, bacterial decomposition taking place on the hydrant — other dogs’ scent-marks stay on it longer than on trunks. When your dog passes the hydrant and gets another dog’s scent, he overmarks it with his own urine.

Possibility to Pee High

A fire hydrant is ideal for your dog to position itself to pee high. No tree branches or other obstacles are preventing the urine from spraying as high as possible.

The Smell of the Hydrant’s Paint

According to some, dogs love the dyes or components of the paints used on fire hydrants. They believe that the smell of the paints, to a certain degree, like dog pee. If a dog passes a fire hydrant, it feels compelled to overmark. There is no scientific proof that this is true, but it is still an interesting view!

Photography of Red Fire Hydrant
Image by Foteros via Pexels

Final Thoughts

It is definitely true that dogs like to scent-mark fire hydrants. Hydrants are ideal vertical objects that comply with the basics a dog needs to scent-mark and overmark. They form part of the natural boundary, are high enough to provide dominance if the dog can pee high enough, and the scent stays relatively long on them.

It is interesting that comic strips and animation films almost always depict dogs urinating against fire hydrants, and now we understand where this cliche originates.