Kathleen Morrill Pirovich: Why are there so many different kinds of dogs?

Why are there so many different kinds of dogs?

The immense physical variety of dogs makes them among the world’s most diverse species and likely the one with the greatest range in size. A Pomeranian, for example, might weigh 2 kilograms, while a Mastiff could tip the scale to 100. So, why is this? And what does a dog’s breed actually say about them? Kathleen Morrill Pirovich explores the dizzying diversity of dogs. [Directed by Anastasiia Falileieva, Studio Plastic Bag, narrated by Bethany Cutmore-Scott, music by Zakhar Bo].


Despite their vast physical diversity, from tiny Pomeranians to massive Mastiffs, most dogs share surprisingly similar personalities. Scientific studies show that only about 9% of a dog's personality can be traced directly to breed, and less than a quarter of their temperament is shaped by genetics at all. Instead, a mix of ancient instincts, individual variation, and environment determines how a dog behaves. The myth that breed predicts temperament, like aggression in pit bulls, rarely holds up under scrutiny.

Dog Breeds Reveal Little About a Pup’s True Personality

Dog breeds show striking diversity in size and appearance, from tiny Pomeranians to massive Mastiffs. Yet, scientists have found that only about 9% of a dog's personality traits can be traced to its breed. While some behaviors, like herding or retrieving, reflect ancient instincts, most personality differences come from individual variation and environment. Genetics matter, but breed alone is a poor guide to predicting how a dog will act.