So, are behavioral differences sizebased? For the most part, the answer is a resounding “No!” Dogs of all sizes love to play chase, fetch, go on walks, run off leash, meet new people, romp with their best dog buddies, participate in training sessions and eat tasty treats. By the same token, dogs of all sizes are vulnerable to sound sensitivity, exhibit separation anxiety and aggression, jump on people inappropriately, bark to excess, chew on shoes, dig in the garden, or have accidents on the floor. They all wag their tails (if they have them!) in joy.
And yet, there are clearly differences between individual dogs, based perhaps on age, gender or the environment in which the dog lives and was raised. While the similarities in dogs of different sizes are far greater than the differences, can we deny those differences?
Science Steps In
A 2010 research study (Arhant, et al.) examined the connection between size and behavior in great detail, addressing these questions: How does guardian behavior toward dogs of unequal sizes influence their dogs’ behavior? How do expectations of dogs based on their size differ? Do people treat large and small dogs differently? In the study, “small” and “large” were defined by weight; dogs less than 20 kg (44 pounds) were categorized as small and those equal to or more than that, as large.
The study’s most important overall finding? There are significant differences in behavior between large and small dogs and between guardians of large and small dogs. The researchers reported that a range of interactions between people and their dogs are related to the size of the dog.
Small dogs were reported to be less obedient, slightly more often aggressive or excitable, and more anxious and fearful. People with small dogs also reported a lower level of consistency in their interactions and enforcement of rules than did those with larger pups.
Much has been made of the practice of treating small dogs like babies, though it’s hardly surprising that it occurs. Babyish features affect human caretaking behavior; we’re evolutionarily hardwired to find big eyes, small size and proportionally large heads endearing. Psychologists call this the “Aww phenomenon.” If babies weren’t so cute, parents could be less likely to respond to their needs, and the offspring would be less likely to survive.
Dogs seem to elicit this same “aww” response in humans, especially small dogs, and even more so, breeds with pronounced juvenile features such as Cavalier King Charles Spaniels, Chihuahuas, Japanese Chins, Pugs and Boston Terriers. Since babies affect our hormones, raising the levels of oxytocin — nicknamed “the love hormone”— it stands to reason that adorable dogs do, too.
Socialization, Training and Other Interactions
Socialization is a key factor when it comes to dog behavior. Typically, large dogs have more opportunities for socialization than small ones. When small dogs are carried around rather than moving around on their own four paws, they have fewer interactions with people and other dogs, which can limit their ability to cope with them. Also, small dogs are often picked up or otherwise physically manipulated, which may result in more negative experiences with humans.
Many say that their small dogs are “people” dogs and don’t like other dogs; lots of people with big dogs say the same thing. Size notwithstanding, positive experiences with other dogs during puppyhood are the best way for a dog to develop good manners. Absent enough of those experiences, dogs of all sizes face social challenges.
Well-trained dogs are always a joy, but training is another way in which interactions between people and dogs differ based on size. Two research studies found that small dogs do not receive as much formal training as large dogs (Kobelt, et al.; Masters and McGreevy). Also, people play fetch more often and do more tugging and nose work with big dogs than with small ones, and are more likely to take them running or biking (Arhant, et al.). Arhant’s study concludes that differences in people’s behavior may account for the higher rates of disobedience in small dogs.