Can Dogs Smell of Fish?

Imagine you and your dog are driving along with the car windows down. Suddenly, you become aware of this terrible, stomach-turning smell. It's like nothing you've ever smelt before, as you take cautious sniffs trying to work out what it is and where it's coming from. 

It occurs to you that the closest comparison is fish, but not just any fish but rancid left-out-in-the-sun-for-days fish. Pyew! 

Thinking it must be the neighborhood, you put the car windows up and the air conditioning on to wait for the bad smell to pass. But it doesn't. In fact, if anything, the fishiness intensifies. As the miles pass but the foul odor doesn't, it begins to occur to you that the smell originates from inside the car. Since it's not coming from you, this leaves one explanation...the fishy smell comes from the dog! 

Your dog may smell as if they've rolled in a pile of rotting fish. but does it bother them? Not in the least! Indeed, they may well look at it as a positive achievement. This is because the bad odor originates from their anal sacs and is a normal way of telling other dogs who they are. 

The anal sacs should empty out harmlessly each time they have a poop, however, this doesn't always happen. If the dog has overfull anal sacs or an infection in one gland, then some of this potent-smelling secretion may leak out. The powerful aroma can then contaminate the dog's coat and transfer to anything they sit on - hence spreading the malodor and sharing it with you. 

Another sign your dog may imminently smell like a fish is if they spend time scooting or sledging along on their bottom. The sensation of the stretched anal sacs can be uncomfortable and instinctively they may try to relieve the pressure by dragging their bottom along the ground. It is an unwritten law that the dog will wait for the most embarrassing moment for you, before they very publically drag their butt along the floor, possibly on an expensive carpet. 

And lastly, full or infected anal sacs can be painful, so if the dog is uncomfortable sitting, seems distressed, and has a fishy smell, then think "anal sacs."

For as long as people have been keeping dogs, they have realized dogs have the unpleasant ability to smell like fish from time to time. The anal gland secretion smells strongly of fish, and although it is a scent signature, under some circumstances it can also be offensive to dogs. Small comfort to us! 

Indeed, experiments in the 1960s whereby behaviorists presented dogs with the anal sac secretions of other dogs got some interesting results. Those presented with the fishy secretion drew back with apprehension and some even recoiled. 

Again in the 1960s, researchers investigating dog anal problems (they must have drawn the short straw) found that whilst its normal for anal sac secretion to empty onto feces,  this isn't always the case. At times of stress, the anal secretion can be squirted, skunk-like, from the anal sacs and travel several feet across the room. 

Quite why scientists had to research this is a mystery. All they had to do was ask a vet, as it's not unusual to be daubed with anal sac secretion when a dog is stressed or upset. 

Believe it or not, anal sacs secretions are an important part of dog communication. That bad, fishy smell is unique to each dog and forms their scent signature. This is what all that butt sniffing is about when dogs meet and greet each other. 

In addition, the anal sacs mark the dog's poop each time they go to the toilet. Again, this marks the poop out as theres and is a signal to dogs that they passed this way. If this seems bizarre to us, be aware that the canine nose is more sensitive to subtle smells than ours. Whilst there's nothing subtle about a strong fishy smell, to a dog it's the equivalent of getting an email describing a recent visitor. 

And as for the science, well that stinky stuff is made up of a mix of different naturally occurring chemicals including:

• ethanol
• acetic acid
• butyric acid
• isobutanol
• propionic acid
• isovaleric acid
• valeric acid
• piperidone

It is theoretically possible to teach a dog to smell like fish, but this is undesirable on many levels. Most importantly, dogs empty their anal sacs at times of stress. It is ethically unjustified and morally cruel to stress a dog with the sole purpose of getting them to empty their anal sacs; besides, why would you do that?

Time is better spent looking out for the dog's health and welfare by promoting healthy poop and anal sacs that empty naturally, thus reducing the risk of infection. 

To do this, a good solid (but not hard) poop is the gold standard. As this is passed, the muscles of the anal sphincter contract in such as way as to milk out the anal sac secretion at the beginning and end of the feces. 

When a dog has diarrhea or eats a low fiber diet, then the poop is less bulky or much softer, and some of the milking effects on the anal sacs is lost. 

This can lead to a gradual accumulation of anal sac secretion within the gland, causing it to stretch. When the secretion is produced more quickly than it drains away, this can lead to impaction and infection. The latter is extremely painful with some dogs becoming feverish, going off their food, and even limping. 

Prompt treatment with pain relief and antibiotics is required in order to save the dog from further distress. In some cases, sedation or an anesthetic is required, in order to flush out the infection and pack the glands with antiobitics.