Hormonal Changes Behind Barking at Other Dogs and Stress-Relieving Responses to Sniffing During Dog Walks

Hello! I am Ansim-i the Dachshund, the Chief Researcher at Magentalab Pet Research Institute! Today, I’ve brought an informative research report for the happy journey of you and your pets.

Have you ever experienced a peaceful walk where your dog suddenly barks madly at another dog or becomes entranced, burying their nose in an unidentified street smell? Pet parents often panic and hastily pull the leash, but in these brief moments, a biochemical “hormone festival” more spectacular than a rollercoaster is happening inside your dog’s body. Why does a typically calm dog turn into the Hulk or roll on the ground in a single second? What exactly is happening in their brain and blood vessels?

1. Causes of Hormonal Changes Leading to Barking and Mounting When Encountering Other Dogs During Walks

Encountering an unfamiliar dog during a walk induces extreme tension for your dog, much like a human suddenly bumping shoulders with a large, intimidating stranger in an alleyway.

Adrenaline and Cortisol Secretion During Unfamiliar Dog Greetings

The moment your dog visually and olfactorily recognizes the other dog, their brain’s hypothalamus immediately rings an emergency bell. At this time, the sympathetic nervous system excites, and the adrenal medulla secretes a massive amount of adrenaline. The heart rate increases rapidly, pupils dilate, and blood rushes to the muscles throughout the body, placing the dog in a “Fight or Flight Response” state ready to engage or escape at any time.

Simultaneously, the level of the stress hormone cortisol spikes. Until they figure out if the other dog is a threat or a welcome friend, cortisol keeps your dog’s vigilance at its peak. To pet parents, it may just look like barking and excitement, but inside the dog, a fierce storm of hormones for survival is raging. If a positive greeting occurs and they find peace by sniffing each other, oxytocin (the hormone of love and bonding) is secreted to lower adrenaline levels and restore peace. However, if the tension remains unresolved during the greeting, they may express their stress through displacement behaviors like mounting, unable to control their excessive excitement energy.

2. The Dopamine Explosion: The Predatory Instinct to Chase Stray Cats and Pigeons

While encountering another dog is a series of tension and vigilance, discovering other animals or small critters like stray cats, pigeons, or squirrels triggers a completely different hormonal system.

Changes in Brain Neurotransmitters When a Dog’s Predatory Instinct is Stimulated

The moment they catch the quick movement of a small animal, dopamine—a neurotransmitter of reward and pleasure—is explosively secreted in the dog’s brain. This is the moment the “Predatory Drive,” which has been dormant deep in the dog’s DNA, awakens.

Dopamine provides the dog with a strong internal motivation: “If I chase and catch that, I will get immense pleasure!” At this moment, the dog exhibits such high concentration on the target that they cannot even hear their pet parent’s voice or feel the pressure of the leash. Because the anticipation and excitement induced by dopamine are highly addictive, a dog that has tasted the joy of chasing a bird once will reflexively pull the leash and run out like a sled dog whenever they see a bird on the next walk. This happens not because the dog is stubborn, but because dopamine has completely taken over the brain’s reward circuit.

3. Dog Nose-work Walks: The Endorphin and Serotonin Effects of Rolling in Strange Smells

During a walk, you may see your dog bury their nose into a specific utility pole, a patch of grass, or even a dead earthworm or unidentified trash, obsessively sniffing it, or even rubbing their body and rolling on it.

Why Dogs Scent Roll on Earthworms and Feces: A Stress Relief Method

For a dog, the act of sniffing, or “nose-work,” is an information-gathering process perfectly identical to a human checking social media and reading internet articles on a smartphone. Complex chemical olfactory information entering through the dog’s nasal mucosa and the vomeronasal organ (Jacobson’s organ) transmits directly to the olfactory bulb in the brain.

At this time, the brain secretes endorphins and serotonin. Serotonin, secreted when analyzing the urine scent left by other dogs to grasp neighborhood trends, provides the dog with emotional stability and calmness. Additionally, the act of rubbing their body on a dead earthworm or a place with a strong odor (scent rolling) is an instinctive behavior from their wild ancestors to hide their own body odor and camouflage themselves with the scent of their prey. When performing this behavior, the dog secretes a large amount of endorphins along with extreme satisfaction, effectively relieving stress. It may horrify pet parents, but for the dog, it is the ultimate natural stress reliever and a healing time akin to receiving spa therapy.

4. Dog Walk Training: How to Walk Without Pulling the Leash and a Management Guide for Pet Parents

Once you understand the action of these complex hormones, it becomes clear how pet parents should handle unexpected situations during walks. It is nearly impossible to control a dog’s hormonal surge with physical force or yelling.

Tips for Calming an Excited Dog During a Walk: Reward Treat Timing

If you pull forcefully on the leash of an excited dog with surging adrenaline and cortisol, the pressure and pain on their neck will actually accelerate the secretion of stress hormones, drastically worsening the situation.

The most effective management method when spotting an excitement trigger (like another dog or cat) is to practice “threshold management” in the early stages before the hormones explode. At a distance where the dog has recognized the stimulus but has not yet lost their reasoning, call their name, and when they make eye contact with you, reward them with a high-value treat. This is a scientific behavior modification method that sets the satisfaction of the gustatory reward obtained by focusing on the pet parent higher than the dopamine obtained when chasing the target.

Additionally, in safe areas, you must allow sufficient sniffing (serotonin secretion) to achieve the essential purpose of the walk. When physical energy expenditure and olfactory information processing are balanced, your dog’s walking manners will naturally improve.

Medical Caution: If your pet shows excessive aggression during a walk or experiences severe anxiety, and you suspect abnormal behavior due to illness or health issues, do not make definitive diagnoses or prescriptions on your own; always consult a veterinarian for an accurate clinical diagnosis.