What your dog’s moods are really telling you
Dogs cannot tell us when something is wrong. They cannot explain that they are in pain, that they feel unsettled, or that something in their body is quietly changing. What they can do is behave. And if we know how to read it, behaviour can be one of the most informative health signals a dog has.
This idea, that a dog’s everyday behaviour is a window into their physical and emotional wellbeing, has been central to veterinary medicine for years, but a landmark study published in 2025 has now quantified this relationship at a scale never seen before, tracking the behaviours of over 47,000 dogs across the United States and building what researchers describe as a crucial baseline for understanding the link between canine behaviour and health.
The largest dog behaviour study ever conducted
Jointly led by researchers from Virginia Tech and the University of Washington, and drawing on data from the Dog Aging Project, the study enrolled 47,444 dogs between 2020 and 2023. Owners completed detailed health and lifestyle surveys, including a standardised behavioural assessment – the Canine Behavioral Assessment and Research Questionnaire, known as the C-BARQ – that is widely used in research settings.
Using statistical analysis, the team grouped dog behaviours into four broad domains: fear, attention and excitability, aggression, and trainability. They then looked at how these domains related to factors including breed, sex, size, spay and neuter status, life stage, geographic region, and time.
The scale of the dataset gave researchers something genuinely powerful: the ability to detect meaningful patterns that smaller studies simply cannot see. As co-lead Dr. Courtney Sexton noted, “When you have a data set this big, you really do have power in numbers.”
What the data revealed
TLDR: Breed, size, sex, and age all matter, but not always in the ways you might expect.
Smaller dogs, for example, tended to show higher levels of fear and attention-seeking behaviour. Older dogs showed shifts in trainability and excitability consistent with cognitive and physical changes associated with ageing. Male dogs differed from females in aggression profiles, while spay and neuter status added further complexity to the picture.
Geographic differences also emerged. Dogs in certain regions of the United States showed higher levels of particular traits – for instance, dogs in the Midwest were reported to be more attention-seeking than dogs in other areas. Whether this reflects genuine regional differences in owner-dog relationships, lifestyle, or breed distributions is a question for future research.
Behaviour and health are deeply intertwined
The study’s central message is that behaviour and health are deeply intertwined. Dogs that displayed shifts in normal behaviour, becoming more fearful, less trainable, or unusually reactive, often had underlying health issues. A dog that suddenly becomes noise-sensitive, less interested in play, or more irritable may be experiencing pain. A dog that becomes uncharacteristically clingy or disoriented may be showing early signs of cognitive decline. Behaviour is not separate from health; it is an expression of it.
The COVID-19 finding
The study had an interesting origin: it was partly motivated by a desire to understand how the COVID-19 pandemic had affected dog wellbeing. When owners’ routines changed dramatically – working from home, spending more time with their dogs, and then eventually returning to offices – did dogs’ behaviour change in turn?
The answer was largely reassuring. Despite the upheaval of pandemic life, there were no substantial changes in dogs’ overall behavioural profiles from year to year. Dogs, it seems, are more adaptable than many owners feared. One exception, however, was trainability; this did show some variation across the pandemic years, suggesting that disruptions to routine may have had a modest effect on how readily dogs engaged with learning.
Behaviour as an early warning system
Perhaps the most important practical implication of this research is the idea of behaviour as a health monitoring tool. We routinely check our dogs’ weight, coat condition, and appetite. We notice limping and take it seriously. But subtle behavioural changes like a dog that used to love greeting visitors but now hangs back, or a dog that has become oddly restless at night, are less often flagged as potential health signals.
The Virginia Tech and University of Washington research team are now using this dataset as a baseline to track how behaviours change as individual dogs age, which will ultimately allow them to identify patterns that predict health events before they become clinical emergencies. It is, in essence, a long-term health surveillance project conducted through the lens of behaviour.
What owners can do right now
You don’t need to be a scientist to make use of this insight. Here are practical ways to use your dog’s behaviour as a health barometer:
Keep a baseline: Know what normal looks like for your individual dog. How eager are they to greet you? How quickly do they settle in the evening? How do they respond to other dogs on walks? Subtle deviations from your dog’s normal are more meaningful than any generic checklist.
Take behaviour changes seriously: A dog that becomes suddenly reactive, fearful, withdrawn, or irritable, especially without an obvious environmental trigger, deserves a veterinary check-up. Pain, thyroid disorders, neurological changes, and even infections can all manifest as behavioural shifts.
Consider life stage: A puppy’s attention-seeking behaviour is normal; the same behaviour in a 12-year-old dog may signal anxiety or cognitive change. Age-related context matters when interpreting what you observe.
Talk to a professional: If your dog’s behaviour concerns you and a health cause has been ruled out, a qualified animal behaviourist or veterinary behaviourist can help you understand what you’re seeing and how to respond to it.
The road ahead
The Dog Aging Project, from which this study draws its data, continues to track the same dogs longitudinally, following them through life stages, health events, and changes in behaviour. As the years accumulate, so too will the insights. We are only beginning to understand the full depth of the behaviour-health connection in dogs, but the early picture is clear: your dog’s moods and behaviours are among the most valuable health signals they have. The more fluently we can read them, the better we can care for the animals who cannot speak for themselves.
Source: Virginia Tech and University of Washington, Dog Aging Project, published September 2025.
