Dog owners might have noticed that their dog is retrieving objects and might have done so since puppyhood. Many dogs love bringing objects to their owner and they do that since they are puppies, often they do not even need any formal training or they do not even need their owner to ask for it.
Why do dogs retrieve objects? The answer to this question lays in the origin of dogs as a species and the thousands of years of human selection. It is thought that the modern dog originated as their ancestors and humans begun to hunt together and that, over the millennia, humans have been selecting the most collaborative dogs. The results of all these selections are still evident in the genetic repertoire of modern dogs, and lead to odd behaviours that might not even be necessary anymore.
In order to understand why dogs retrieve, we need to know where this behaviour is derived from. Several behavioural patterns that we see in dos today, originated from hunting behaviour and, through years and years of human selection, they have been sort of frozen on a specific phase. For example, herding dogs stare at the animals that they are herding, the same way a predator stare at the prey they are stalking. Similarly, retrieving behaviour derives from the behaviour of a predator that carries their prey somewhere they can consume it safely.
Dogs are also very playful and keen on learning new things and they learn through play. Oftentimes, as soon as a puppy learns to carry objects with their mouth, this becomes a fun new game to play with their owner or littermates. The behaviour gets reinforced and it protracts in adulthood.
Federica Pirrone, Mariangela Albertini, Patrizia Piotti researchers at UNIMI Veterinaria