Understanding Canine Behavior Through Physiology, Genetics, and Environmental Context
Behavior doesn’t happen in a vacuum. Every bark, lunge, or flattened ear is part of a larger conversation, a dialogue shaped by health, history, genetics, and the world around us. Dogs respond not just to what’s happening in the moment, but to the countless layers of experience and biology that support—or strain—their wellbeing.
To truly understand a dog’s behavior, we need to look past the surface—beyond training cues, beyond emotion, and explore the systems working quietly behind the scenes. The brain, the body, and the environment are all in constant conversation, each influencing the other in ways we might not notice.
It’s a bit like a tower of blocks: what we see on the outside tells only part of the story. Only gives us a vague idea of its structural integrity. To understand the whole picture, we have to look deeper, into the physiology, the stress, and the invisible connections that keep the tower standing.
Health: From Eye Care to Skin Care, Weight to Wellbeing
Health is one of the most important factors to consider when evaluating behavioural change, yet it is often the last place many think to look. A dog’s health encompasses far more than what meets the eye, and even subtle imbalances can influence mood, energy, and reactivity.
You Are What You Eat
It’s a common saying, but what does “you are what you eat” really mean when it comes to dogs?
In short, the food a dog consumes directly affects their physical health, mental state, and overall well-being. Nutrients from food provide the building blocks that support every aspect of the body’s function. A balanced diet supports stability and resilience, while an unhealthy one can lead to both physical and behavioural issues.
Understanding what “healthy” means for an individual dog is not always straightforward. Like all domesticated species, dogs have general nutritional guidelines for macronutrient intake. However, factors such as food quantity, digestibility, and individual sensitivities complicate the picture. The increasing prevalence of canine obesity and food allergies has further highlighted the strong connection between diet and behaviour.
Weight of the Matter
Weight and body condition score (BCS) play a significant role in both physical comfort and behavioural expression. A 14-year study conducted by the Purina Institute examined Labrador Retrievers maintained at a lean body condition (BCS 3–4) versus those at a “normal” condition (BCS 4–5). The results were striking: lean-fed dogs showed a 50% decrease in the incidence of hip dysplasia, cruciate ligament tears, and osteoarthritis (OA) development. Additionally, when hip dysplasia did occur in the lean group, it was markedly less severe.
It is important to note that these findings compared lean dogs to those of normal weight, not overweight or obese dogs. From this, we can infer that the frequency and severity of these conditions would likely be much higher in heavier individuals. We will discuss how these health factors influence behaviour later in this essay, but it is already clear that maintaining an optimal body condition can heavily impact the long-term quality of life of an animal.
Allergic, Reactive, and Worked Up
Dietary and environmental allergies can have profound impacts on both physical and behavioural health. Food allergies occur when the immune system mistakenly identifies certain proteins as threats, triggering inflammation in the gastrointestinal tract and resulting in symptoms such as vomiting, diarrhea, gas, abdominal pain, and malabsorption.
To use a familiar analogy: just as we learned in school that mitochondria are the powerhouse of the cell, the gut can be considered the powerhouse of the body. Its ability to process nutrients directly determines how well the body functions. When immune responses or inflammatory reactions disrupt the gut’s delicate microbiome, the system’s ability to process and utilize fuel breaks down. This can also occur when animals consume too much, too little, or an improperly balanced diet.
The gut’s function is closely tied to the body’s ability to produce neurotransmitters such as serotonin, norepinephrine, and GABA, compounds essential for regulating mood, pain perception, and emotional balance. When the gut is inflamed or lacking proper nutrients, production of these inhibitory neurotransmitters decreases. This imbalance can lead to heightened anxiety, irritability, and reactivity. Moreover, immune responses that begin internally often manifest externally: when nutrient absorption and repair processes are disrupted, the skin’s natural healing cycle can be compromised. This may result in rashes, infections, or chronic itchiness—all of which can further contribute to discomfort and behavioural change.
Where does it hurt?
Pain changes everything. It’s not just a physical sensation; it alters perception, mood, and behavior, sometimes in ways that are hard to see. Just as subtle changes in diet or weight can ripple through a dog’s wellbeing, pain, whether acute or chronic, can shift the way a dog moves, reacts, and interacts with the world around it.
A real pain in the….
Pain, almost everyone has experienced it in their lives, from stomach aches to broken bones. Pain is a part of life. But what causes pain, and how does it affect the body?
Did you know that pain can alter the structure and function of the brain? Acute pain: defined as a sudden, sharp, and short-lived pain that typically arises from a specific injury or medical condition. It can shape how a dog responds to the associated “trigger” in the future, I say trigger in quotes because the associated trigger and the actual trigger of the pain may not always align. Dogs are very intelligent and take a lot of information from their environments. This can become tricky, however, when an understanding of the function of one’s body is not understood.
When out for a walk one day, your dog may see the mailman pulling in, having never been concerned with him in the past, your dog continues to walk on, but mid-step, after noticing the mailman your dog catches its dewclaw on a bramble, and they experience acute pain in that area. Your dog never noticed the bramble, but it did notice the mailman. Sometimes these experiences can reshape the brain's response to the seemingly associated stimuli, leading to defensive behaviors to “prevent” that experience in the future.
Aching to Be Understood
Now, what about chronic pain? For some—myself included—chronic pain can be a daily occurrence: the body sending out pain signals multiple times a day, every day. The intensity and frequency can vary depending on a range of factors such as activity level, inflammation, stress, or weather changes. Chronic pain can stem from many causes, including deficiencies in pain-inhibitory mechanisms, overproduction or hypersensitivity to excitatory signals, orthopedic conditions such as arthritis, nerve damage, etc.
Regardless of the underlying cause, the resulting pain profoundly impacts both the body and the brain. Chronic pain is not just a physical experience; it can alter the brain’s structure and chemistry over time. Studies have shown that persistent pain can decrease gray matter volume in areas responsible for emotional regulation, memory, and decision-making. It can also raise baseline stress levels, elevate blood pressure, and impair focus and attention. Over time, this chronic stress state can contribute to immune dysregulation, increasing the risk of autoimmune or other systemic conditions.
When pain persists, the nervous system often becomes “stuck” in sympathetic activation—the body’s fight-or-flight mode, making it difficult to return to a parasympathetic, rest-and-digest state. This constant physiological tension keeps cortisol and adrenaline elevated, further amplifying pain perception and emotional reactivity.
For dogs, this means that behaviours often labeled as “stubborn,” “grumpy,” or “reactive” may actually be expressions of discomfort or fatigue from chronic pain. Subtle changes, like slower movement, irritability during grooming, or avoidance of certain activities, can be early indicators of ongoing discomfort. Unlike humans, dogs can’t verbally articulate their pain, so their behaviour becomes their language.
Recognizing and addressing chronic pain is therefore essential, not only for physical welfare but also for emotional and behavioural balance. By learning to interpret these signals with empathy, we can better support our canine companions, helping them shift from surviving in discomfort to thriving in comfort.
To the Window, to the Ball, down the Very Slippery Hall
How can the environment impact behavior?
It all circles back to the root of our story: association and the biological drive for safety and self-preservation. When an animal experiences something stressful or painful, the brain uses context clues from the environment to understand what happened. It begins piecing together sights, sounds, textures, and smells to form a generalized map of what’s safe and what’s not.
The environment becomes a teacher, sometimes a kind one, sometimes not. Dogs learn to associate certain spaces, surfaces, or sounds with comfort, or conversely, with danger or discomfort. A dog who slips on a tile floor once may approach all shiny floors with hesitation. Another who hears thunder just before a painful event might later shake at the sound of distant rain. Even seemingly harmless factors, like echoing hallways, flickering lights, or the buzz of an appliance, can quietly elevate a dog’s stress levels over time.
Stress itself is not inherently bad; it’s a survival mechanism. The body releases cortisol and adrenaline to prepare for action, helping animals adapt to immediate challenges. However, when stressors are constant like a chaotic household, inconsistent handling, or environmental discomfort, those systems never fully reset. This creates a state of chronic stress, where cortisol remains elevated and the body struggles to return to balance.
Chronic environmental stress can have significant physiological and behavioural consequences. Prolonged exposure to stressful conditions can suppress the immune system, delay healing, disrupt sleep, and even change how the brain processes information. Dogs living in high-arousal or unpredictable environments may show increased reactivity, hypervigilance, or frustration-related behaviours such as barking, pacing, or destructive chewing. Over time, these responses become less about the environment itself and more about the body’s conditioned expectation that stress is coming.
Small changes in the environment can have surprisingly big effects. Slippery floors can create physical insecurity; loud neighborhoods can lead to sensory overload; even rearranging furniture or changing routines can unsettle some dogs. The key is recognizing that the environment isn’t just a backdrop—it’s an active participant in shaping behaviour.
By observing how dogs move through their spaces, where they hesitate, where they relax, how they choose to rest, we can identify sources of stress that might otherwise go unnoticed. Sometimes, improving behaviour isn’t about more training, but about better design: secure footing, quiet resting spaces, predictable patterns, and environments that communicate safety.
In the end, a dog’s behaviour is as much a reflection of their surroundings as it is of their internal state.
Jenga, Canine Edition
We’ve all played Jenga (or at least watched someone else anxiously pull a piece), but in case you haven’t, the premise is simple: remove tiles one by one and try not to be the one who makes the tower fall. Easy enough—until it isn’t.
Now, imagine that tower as a representation of your dog’s emotional wellbeing. Each block is a part of their stability, and every stressor or negative experience removes a piece. Let’s say your dog is in pain—go ahead and take a piece from the foundation layer. The tower’s structural integrity is already shaky. This unsteadyness now makes it so that the pieces being removed that may not have impacted the towers structure instead push it closer and closer to collapse. A small trigger that your dog may have brushed off now takes a piece that it wouldn’t have on a day where the tower was more stable. Later that day, the mailman arrives, and your dog loses it—another piece gone. As the day goes on, small frustrations continue to chip away until the tower finally collapses.
This is what's known as trigger stacking.
As stressors pile up without time to decompress (rebuild), the tower (your dog’s emotional resilience) loses integrity. When it becomes too unsteady, even the tiniest bump can send everything crashing down.
Behavior, much like that Jenga tower, is a complex structure made of many interlocking blocks. And the factors that can remove those blocks are often shaped early in life as the brain develops, learns, and adapts to the world.
Routine and Response
Dogs aren’t the only ones who can become trigger-stacked. This physiological process is something all species experience, it just shows up differently for each of us. Over the past decade, more people have started to recognize how subtle, layered stressors influence everyday behavior. Every small frustration or unmet need adds up, shaping how we respond to the world around us.
Think about it: you wake up with a headache. The footsteps of your upstairs neighbor ,something you usually tune out, suddenly feel unbearable. How quickly something that may have previously caused minor irritation has now turned to anger. You find yourself glaring at the ceiling or even grabbing the broom for a few pointed taps. That reaction doesn’t come from nowhere; it’s a stack of small stressors, layered until the structure gives.
Now, how does this relate to our dogs?
Our health and emotional wellbeing have a profound effect on our animals—often in ways we don’t even realize. As someone who lives with chronic pain, I notice this firsthand. On days when the pain is bad, my patience for normal behaviors like excited jumping, barking, pawing, shrinks. What might have felt playful yesterday feels overwhelming today. My dog doesn’t know why I’ve changed. All she perceives is that her behavior suddenly earns tension instead of play.
The same thing happens in subtler moments, too. Maybe you wake up with a fever and skip your usual morning walk. To you, that’s self-care. But to your dog, that routine is a cornerstone of their day, a way to meet her needs. When that disappears, the energy and expectation don’t vanish; they shift, often into restlessness or frustration.
Even tiny cues can ripple through the connection. When we see another dog on a walk, we might unconsciously tighten the leash, hold our breath, or stiffen our posture. Our dogs feel those changes instantly. Maybe they wouldn't have noticed this trigger, or maybe their reaction wasn't going to be big, but now we've communicated through our body language or tension on the leash that something in the environment has made us uneasy, and they respond in kind.
Our routines, our energy, our body language, these are part of our dogs’ environments as much as their food, toys, and beds are. When our own tower of stress starts to wobble, theirs often does too.
Little things in our lives create big shifts in theirs, and when we learn to recognize those patterns, we begin to understand that behavior—human or canine—is never happening in isolation.
Old Instincts, New World
It’s estimated that humans began domesticating dogs nearly 32,000 years ago—which really helps put into perspective how we got from wolves to today’s pugs. But what does that long history mean for our dogs? What’s happened over all that time, and why did we create the breeds we have today?
For thousands of years, dogs were woven into nearly every aspect of human life—hunting, herding, guarding, powering machinery, entertainment and so much more. Each breed was hand-tailored for purpose: dogs with the best instincts, structure, and drive were bred to refine their usefulness. Over generations, we shaped their very genetic makeup to suit our needs.
But as the world changed, our needs did too. The jobs dogs once held began to fade, yet the breeds themselves didn’t disappear. Instead, we started valuing them for personality and companionship. While some breeds were created specifically for those roles, we often find ourselves drawn to dogs whose genetics were never meant for the modern living room.
So what happens when you place a cattle dog in a suburban home? When something built to run the fields now resides on your sofa? Do those old instincts vanish—or do they find new ways to surface?
A common statement I hear from owners of Australian Cattle Dogs, sounds a little like this: “They keep biting the kids’ ankles,” or “They snap when the vet tries to touch them.” Biting doesn’t fit the new rules of domestic life—but these dogs weren’t designed for the living room. Generations ago, they were prized for their ability to push, nip, and stand their ground with cattle. Control was their job. Even if that’s no longer their purpose, how can we expect a dog to ignore what’s been written into every cell of its being, to fight what its genetics tell it to do?
We’ve created a world with structure, rules, and expectations that often don’t match the genetic blueprints we once so delicately crafted. When an animal finds itself in an environment that doesn’t meet its needs, it will seek ways to fill that gap on its own. These are the behaviors we often label as “undesirable”: the sight hound who can’t resist chasing the cat, the American pit bull terrier who lunges at other animals on walks, the cattle dog who herds children, or the dachshund whose shrill alarm barks pierce the quiet.
Even in our modern world, those ancient drives persist—and not just in dogs. Humans, too, seek to satisfy instincts in new ways. I recently heard someone describe scrolling social media as a form of foraging: an echo of the same instinctual behavior our ancestors needed to survive. We can’t erase thousands of years of evolution; we simply adapt it.
The difference is that dogs don’t understand why their instincts don’t fit this new world—they only know the urge itself. That drive is as old as their breed, and it doesn’t vanish just because the fields have turned into living rooms.
Beyond the Bark: Gabby’s Story
Not all pain is visible. Just as a person may endure a sore leg without limping or complaining, a dog can experience discomfort in ways that are subtle, or easily misunderstood. Gabby, an eight-pound Dachshund, illustrates this perfectly. She struggled with severe separation anxiety, noise sensitivity, and reactivity toward other dogs. At first glance, she seemed energetic, playful, even fearless—more like a tiny wind-up toy than a dog in distress.
A closer look, however, revealed a different story. Gabby often sat with her legs splayed wide, her vulva touching the ground, or her legs splayed flat out behind her. When her owner reached toward her lower back, she would lick or gently mouth their hands. These subtle signals prompted a veterinary evaluation, which confirmed a grade II luxating patella. Surgery repaired the knee, but her behavioral challenges only partially improved.
Gabby’s experience demonstrates how health and pain interact with behavior. Each painful episode during her development taught her brain to associate certain environments and events, like playing with larger dogs or sudden noises, with danger. Her nervous system, influenced by both acute and chronic pain, reinforced defensive behaviors such as barking, lunging, and exaggerated displays. This is trigger stacking in action: layers of stress, pain, and environmental stimuli compounded, leaving her emotional “tower” unstable.
Her genetics and breed instincts also played a role. As a small, active dog, bred for loud alert barking when prey was located. Her body built for mobility and alertness, but not necessarily for enduring repeated discomfort without a coping strategy. Combined with her environment—a loud neighborhood, unpredictable stimuli, and unpredictable routines – her learned responses became adaptive in her mind, even if they appeared “undesirable” to her humans.
Recovery required addressing every layer: health (surgery and physical therapy), routine and environment (predictable structure, controlled exposure), behavioral support (retraining associations and stress management through medication), and patience as her nervous system recalibrated. Over time, Gabby learned that she could move through her world safely, without reacting defensively to every stimulus.
Gabby’s story is a reminder that behavior is never a single cause, but the sum of many factors: health, pain, environment, routine, and genetics all interacting. By examining each piece of the puzzle, we gain insight into why dogs act as they do, and how we can support them in finding balance, confidence, and safety.
Seeing the Whole Dog
Behavior is never without cause, it serves a purpose. Every bark, lunge, or hesitation is the product of countless interacting layers: genetics, health, pain, environment, routine, and past experience. Gabby’s story reminds us that what we see on the surface is only part of the picture; beneath it lies a network of influences shaping how a dog perceives and responds to the world.
Understanding the whole dog requires curiosity, observation, and empathy. It means recognizing that a seemingly “stubborn” or “aggressive” behavior may be a signal of discomfort, stress, or unmet needs. It means appreciating that small changes, whether in diet, schedule, environment, or our own energy, can ripple through a dog’s experience in profound ways.
By viewing behavior as a conversation between body, mind, and environment, we shift from reacting to responding. We begin to anticipate triggers, support wellbeing, and create conditions where dogs can thrive—not just survive. Just as we stack and rebuild towers carefully at the beginning of every game of Jenga, we can help our dogs rebuild emotional resilience, one block at a time.
