Where Is Your Pet’s Stress Really Coming From?
A practical framework for supporting your pet’s wellbeing
We talk a lot about stress in our behavior consultations—how it affects our dogs and cats, why some animals seem more reactive than others, and what we can do about it. But stress itself isn’t inherently bad. In fact, the stress response is an important survival mechanism that helps animals (including us) adapt to an ever-changing world.
The problem arises when that system is activated too strongly, for too long, or when significant stressors occur during critical developmental periods in early life. That’s when we start to see the fallout: from fear and anxiety to immune system dysfunction and chronic inflammation to maladaptive behaviors that can put our pets and us at risk and strain the human-animal bond.
The good news? There’s a practical framework we can use to systematically identify where stress might be coming from in our pets’ lives—and, more importantly, what we can do about it.
Understanding the Stress Response
The stress response system is made up of complex and interconnected networks within the brain and body. This system is so important for survival that it’s been conserved throughout evolution, which means the networks that drive your stress response are nearly identical to those that drive your dog or cat’s stress response. Whenever we perceive a stress or a threat, the first phase of our stress response is activation of the sympathetic nervous system, or the “fight or flight” response. If you’re experiencing an acute stress (let’s say you’re in an argument with your boss), you might feel this in your body as your heart racing, muscles tensing, or breaking out into a sweat. Helpfully, we can also usually see clear signs of our pet’s fight or flight response kicking into gear. Those signs include panting, dilated pupils, piloerection (hair standing up along the neck and back), and tense or trembling muscles.
The second phase of the stress response system involves activation of the hypothalamic-pituitary-adrenal (HPA) axis. This results in the release of cortisol, also known as the “stress hormone,” which prompts further changes in the body in order to respond to the stress. While this is very helpful in the short term, long term activation of the HPA axis can lead to a whole host of problems including metabolic disorders, inflammation, cognitive deficits, immune suppression, as well as depression and anxiety. And while chronic HPA axis activation is a huge concern, it’s tricky to measure and monitor directly in companion animals.
Two Types of Stressors
Stressors generally fall into two categories:
Physical stressors have a direct impact on physiological functions. These include things like wounds from a fight, inflammation from an infection, and joint pain and disfunction from arthritis. Physical stressors are often (though not always) easier to identify and address with veterinary care.
Psychological stressors are trickier. These might include being in an environment where your pet has previously experienced something frightening or painful, conflicts with other animals in the household, unpredictable events, or interactions with humans that feel threatening. Psychological stressors can be harder to pinpoint because they depend on your individual pet’s perception and history—not just the objective situation.
Why Some Animals Are More Affected Than Others
If you’ve ever wondered why your dog reacts so differently to stress than a friend’s dog, or why one of your cats handles change easily while another falls apart, you’re not imagining things. Several factors influence how intensely an individual animal responds to stressors.
Early Life Experiences
What happens during the early weeks and months of an animal’s life (and what happened in their mother’s life!) has lasting effects on how their stress response system functions. Lack of sufficient maternal care, inadequate socialization, or exposure to significant stressors during development can literally change how the HPA axis operates at a cellular level. These animals often grow up to be more reactive to stressors as adults—not because they’re being dramatic, but because their brains and bodies were wired differently during early development.
This is one reason why two dogs from different backgrounds might respond so differently to the same situation, even if they’ve lived in similar environments as adults.
Chronic Health Conditions
An animal who is already dealing with a chronic condition—allergies, gastrointestinal issues, pain, skin problems—has less capacity to handle additional stressors. Think of it like a bucket that’s already partially full: it takes less to make it overflow. This is why addressing underlying health issues is so important when working on behavioral concerns. A cat whose skin is constantly itchy or whose gut is chronically inflamed is operating with a stress bucket that never fully empties.
Individual Differences and Temperament
Just like people, animals have individual differences in temperament that affect how they perceive and process the world. Some animals are more sensitive to sensory input, more attuned to subtle changes in their environment, and more deeply affected by both positive and negative experiences. This trait—called sensory processing sensitivity—isn’t a disorder; it’s a variation in how the nervous system works. But it does mean these animals may need more support and more careful management of their environments.
The Five Domains: A Framework for Stress Assessment
So how do we actually identify where stress might be coming from? This is where a model called the Five Domains model is incredibly useful.
You may have heard of the “Five Freedoms” of animal welfare—freedom from hunger, discomfort, pain, fear, and the freedom to express normal behavior. While this framework shaped animal welfare thinking for decades, it has some limitations. It focuses primarily on avoiding negative states rather than promoting positive ones, and “freedom from” can be misinterpreted as meaning complete freedom from these experiences, which isn’t realistic in all cases.
The Five Domains model offers a more nuanced approach. It recognizes that animal welfare exists on a spectrum from negative to positive, and it emphasizes that what matters to animals is their subjective experiences—how they actually feel about their life.
The model includes four physical/functional domains (Nutrition, Environment, Health, and Behavioral Interactions) that all feed into a fifth domain: Mental State. Let’s walk through each one with an eye toward identifying potential stressors and opportunities for improvement.
Domain 1: Nutrition
This domain encompasses everything related to food and water: availability, quality, quantity, and variety.
Potential stressors to consider:
Is fresh water always accessible? Some pets are particular about water freshness or bowl placement.
Is your pet eating enough? Too much? Hunger and the discomfort of obesity are both stressors.
Does mealtime create anxiety? Competition with other pets, unpredictable feeding schedules, or difficulty accessing food can all be sources of stress.
Are there any food intolerances or allergies creating chronic discomfort?
Opportunities for positive experiences:
Food variety (when appropriate and introduced properly) can be enriching
Using food for mental stimulation through puzzle feeders or scatter feeding
Making mealtimes predictable and safe
Domain 2: Physical Environment
Your pet’s physical surroundings have a profound impact on their wellbeing. This includes temperature, lighting, air quality, noise levels, substrates (what they walk and rest on), and opportunities for rest and sleep.
Potential stressors to consider:
Is your pet too hot or too cold? Remember that their comfort range may differ from yours.
Are there loud or unpredictable noises? Construction, traffic, household appliances, or even TV sounds can be stressful for some animals.
Does your pet have a quiet, safe place to retreat and rest undisturbed?
Is the lighting appropriate? Access to natural daylight matters, and some animals are sensitive to certain types of artificial lighting.
Are there strong odors that might be aversive? Air fresheners, cleaning products, or scented candles that seem pleasant to us may be overwhelming to animals with much more sensitive noses.
Opportunities for positive experiences:
Access to outdoor spaces or windows with views
Varied, novel environments for exploration (sniff walks for dogs, catios for cats)
Comfortable resting spots in different locations
Domain 3: Health
Physical health has obvious implications for welfare. Pain, illness, and functional limitations all create stress.
Potential stressors to consider:
Is there any undiagnosed or undertreated pain? Chronic pain is extremely common and often underrecognized in cats and dogs.
Are there skin conditions causing itching or discomfort?
Gastrointestinal issues? Nausea, cramping, or irregular bowel movements are all stressors.
Is your pet at a healthy weight? Both obesity and being underweight affect quality of life.
Are there sensory deficits (vision, hearing) that might be creating confusion or anxiety?
Opportunities for positive experiences:
Proactive pain management
Regular veterinary care that catches problems early
Appropriate exercise and physical conditioning
Addressing chronic conditions rather than just managing acute flare-ups
Domain 4: Behavioral Interactions
This domain is where the Five Domains model really shines compared to older frameworks. It encompasses your pet’s interactions with their environment, other animals, and humans—with a particular focus on agency.
Agency is the capacity to engage in voluntary, self-generated, goal-directed behavior. These behaviors are intrinsically rewarding—animals don’t need external rewards to find them satisfying; the ability to make choices and influence outcomes is reinforcing in itself.
Animals can exercise agency through four pathways:
Choice — The ability to make decisions about their own behavior and environment. Does your pet get to choose where to rest, when to interact, what to explore?
Control — When animals learn that their behavior can reliably and predictably influence outcomes, they gain a sense of control. This is one of the many benefits of positive reinforcement training—it teaches animals that their choices matter.
Challenge — Appropriate challenges help animals develop problem-solving skills and build competence. The key word is appropriate—challenges that exceed the animal’s current skill level lead to frustration, fear, or anxiety rather than growth.
Competence — When animals have the tools and strategies to meet challenges successfully, they develop competence, which enables them to handle future challenges more effectively.
Potential stressors related to agency (agency impeded):
Invariant, confined, or barren environments with nothing to do
No ability to escape or avoid things they find aversive
Restricted movement (always on leash, always crated, small living space)
Inescapable sensory stimuli (can’t get away from noise, light, or other animals)
Lack of opportunity to forage (meals always in a bowl with no effort required)
Potential stressors related to other animals:
Ongoing conflict with housemates
Threats from other animals with no ability to retreat (this can include encountering other animals on leash or when approached while confined)
Social isolation
Potential stressors related to humans:
Handling that is rough, forceful, or unpredictable
Punishment-based training approaches
Angry, loud, or impatient human behavior
Interactions that ignore the animal’s communication signals
Opportunities for positive experiences:
Environmental enrichment that encourages exploration and problem-solving
Puzzle feeders and foraging opportunities
Training using positive reinforcement, which builds both competence and a sense of control
Play—both with humans and, for social animals, with compatible animal companions
Ability to retreat and have “alone time” when desired
Interactions with humans who are patient, calm, and responsive to the animal’s signals
Domain 5: Mental State
The first four domains all feed into this one. Mental state is the cumulative effect of everything else—the animal’s overall subjective experience of their life.
An assessment using the Five Domains isn’t just asking “is this animal free from suffering?” It’s asking “does this animal have opportunities to experience positive mental states?” Things like pleasure from eating, comfort in their environment, contentment from health, and the satisfaction of exercising agency all contribute to positive welfare.
When we address problems in Domains 1-4, we’re not just removing stressors—we’re creating conditions for the animal to thrive.
Putting It All Together
Here’s the practical takeaway: when you’re trying to understand why your pet might be stressed, or when you’re looking for ways to improve their quality of life, use these five domains as a checklist.
Walk through each domain and honestly assess what’s working and what might need attention:
Nutrition — Is my pet eating and drinking well? Is mealtime a positive experience?
Environment — Does my pet have access to comfortable temperatures, appropriate lighting, low-stress noise levels, and safe places to rest?
Health — When did my pet last have a thorough veterinary exam? Could there be underlying pain or illness affecting their behavior?
Behavioral Interactions — Does my pet have opportunities to make choices, exercise control over their environment, face appropriate challenges, and build competence? Are their interactions with humans and other animals positive?
Mental State — Considering all of the above, is my pet experiencing more positive states than negative ones overall?
Remember that these domains interact with each other. An animal dealing with chronic pain (Domain 3) may have less capacity to engage with enrichment activities (Domain 4). An animal in a noisy, chaotic environment (Domain 2) may eat poorly (Domain 1). Addressing issues in one domain often has ripple effects across the others.
And remember that this isn’t about achieving perfection—it’s about thoughtful, ongoing attention to your pet’s needs as an individual. What stresses one animal might not bother another at all. The Five Domains gives you a systematic way to consider the whole picture and identify where you might be able to make meaningful improvements.
Want to discuss this topic with me and Valerie Bogie live? Join us for our monthly Zoom discussion on Tuesday, December 16 at 5 pm US Central Time. Bring your questions about stress, the Five Domains, or how to apply this framework to your own pet’s situation. This discussion is exclusive for paid subscribers and a registration link will be sent out tomorrow.
References:
Godoy, L.D., et al. (2018). A Comprehensive Overview on Stress Neurobiology: Basic Concepts and Clinical Implications. Front. Behav. Neurosci. 12, 127. https://doi.org/10.3389/fnbeh.2018.00127
Mellor, D.J., et al. (2020). The 2020 Five Domains Model: Including Human–Animal Interactions in Assessments of Animal Welfare. Animals, 10, 1870. https://doi.org/10.3390/ani10101870
Littlewood, K.E., Heslop, M.V., & Cobb, M.L. (2023). The agency domain and behavioral interactions: assessing positive animal welfare using the Five Domains Model. Frontiers in Veterinary Science, 10, 1284869.
Špinka, M. & Wemelsfelder, F. (2018). Environmental challenge and animal agency. In Animal Welfare (Ed. 3), pp. 39-55.