Aug 21, 2023

Longevity for dogs: how their behaviour changes as they age?

An overview of veterinary studies looking at behaviour problems, personality changes and cognitive aging

As dogs go through different life stages, it is normal for their behavior and personality to change as well. Recent veterinary research has provided insights into these age-related shifts in temperament and cognition. Understanding how dogs' behaviour evolves over their lifespan allows us to provide care tailored to their needs at every stage.

Studies found some personality traits like activity and independence gradually decline from puppyhood into adulthood. However, other traits like novelty seeking remain stable until middle age when they diminish. Problem orientation increases during adolescence and early adulthood before leveling out. There are also individual differences, with some dogs changing more drastically.

While these age-related personality and behavior changes occur on an individual level, research has also revealed some overall trends in how dogs' temperaments evolve over their lifespan.

Looking at group changes across life, activity and novelty seeking decline most in middle age. Problem orientation, meanwhile, increases substantially during adolescence and continue rising into adulthood before stabilising.

Relationships between age and three personality trait scores of the dogs: activity independence (A), novelty seeking (B) and problem orientation (C)

As dogs age, they may interact less with people, sleep more during the day, and show less interest in play or walks. Some elderly dogs become anxious or disoriented in familiar environments as cognitive changes occur.

Recent research has revealed some overall trends in how dogs' activity levels change across their lifespan. Studies have found that activity declines most noticeably in middle age for dogs. This aligns with the idea that age-related changes correlate with the proportion of lifespan completed rather than exact years alive.

Predicted values of dog physical activity (PA) lifestyle (A), PA intensity (B), and PA duration (C) by dog size. Dog size is presented as the midpoint of the following 6 categories: 0–9.9 kg, 10–19.9 kg, 20–29.9 kg, 30–39.9 kg, and >40 kg.

When looking at environment, research showed rural dogs are generally more active than urban or suburban dogs, especially in youth. However, these activity differences based on housing environment diminish in older dogs. Additionally, larger dogs were found to be more active than smaller dogs on average, but this size difference did not vary substantially with age.

Predicted values of dog physical activity (PA) lifestyle (A), PA intensity (B), and PA duration (C) by environment type.

Estimates vary, but somewhere between 14-22% of geriatric dogs develop more severe behavioural changes consistent with canine cognitive dysfunction syndrome (CCD). This involves progressive neurodegenerative changes in the brain leading to decline in cognitive functions like learning, memory, and awareness. Dogs with CCD may fail to respond to commands, have accidents in the house, or get lost in familiar areas. They often pace, wander aimlessly, or stare blankly at walls. The acronym DISHA summarises the common signs of CCD: disorientation, altered social interactions, sleep-wake cycle disturbances, housesoiling, anxiety, and changes in activity levels.

Disorientation → Dogs may seem confused about their surroundings, get lost in familiar places, stare blankly, or have decreased response to stimuli.
Alterations in social interactions → Dogs may show less interest in attention, fail to recognise familiar people, or have increased irritability.
Sleep-wake cycle disturbances → Dogs may be restless at night, wake their pet parents, or sleep more during the day.
Housesoiling → Previously housetrained dogs may eliminate indoors or lose their signalling to go out.
Anxiety → Dogs may vocalise, pace, or show fear and phobias to sounds or situations.
Changes in activity levels → Dogs may seem apathetic and disinterested or exhibit repetitive movements.

Other age-related health issues impact the development and severity of CDS in senior dogs. One of the most significant factors is hearing loss, which becomes increasingly common as dogs age. Over 60% of dogs over the age of 10 have some degree of hearing impairment. Deafness prevents dogs from perceiving auditory cues and stimuli, which can lead to disorientation, altered social interactions, and anxiety. Managing hearing loss through medications, environmental modifications, and training can help mitigate these effects.

Diseases that damage the brain, like encephalitis, brain tumors, and strokes, can also accelerate dogs' cognitive decline. Even when these conditions are treated, they often leave permanent damage that impairs memory, learning, and executive function. Kidney disease and resulting toxicity also link to cognitive dysfunction, likely because they impact blood flow to the brain. Controlling other health problems can potentially slow dementia progression.

Caring for a dog with CCD increases burdens on pet parents in various ways. They limit walks and activities to accommodate their dog’s reduced abilities. House soiling and other behaviours may require more diligent supervision. Pet parents can feel guilty leaving their disoriented dog home alone. While challenging, the loving bond remains and most pet parents deeply cherish the time left together.

Older pet owners tend to have more active dogs than younger ones. While counterintuitive, potential reasons for this include retirement giving older adults more time to exercise and interact with their dogs. Pet parent's age appears unrelated to the intensity of dog activity, suggesting these measures capture somewhat distinct aspects of physical activity.

Predicted values of dog physical activity (PA) lifestyle (A), PA intensity (B), and PA duration (C) by owner age.

It's important not to attribute all behavioural changes in senior dogs to pathology. With age, dogs may simply prefer more rest. Breed traits like retrieving may diminish. But their characteristic spark and lovable nature last a lifetime. Subtle changes are inevitable; dramatic shifts merit discussion with a vet. There’s no need to just “write things off” as old age.

This post is part of my deep dive into the topic of longevity for dogs to understand how can we help our best friends live longer and healthier lives. This is a complex topic and any attempt to compress it into a digestible post may look like an oversimplification. If you want to go deeper, below you can find some papers that helped me write this post.

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