The relationship between the domestication of canines and their cognitive ability has been a topic of intense research and debate among evolutionary biologists. A group of researchers have published in their recent work in the Journal of Royal Society Open Science, that the dog's brain underwent almost a 46 per cent reduction in size over almost 5000 years. The scientists find a direct correlation between the reduced size of the brain and their domestication by humans. In the Neolithic ages, ancestral dogs had a brain size similar to that of their wolf relatives. However, researchers imply that shrinking of the brain does not imply a decreased cognitive ability and does not explain why your Yorkie drinks from a muddy puddle and eats its own poop.

“The way our dogs live nowadays doesn’t give them the opportunity to always express most of their intelligence,” said Dr Thomas Cucchi, first author of the study from the French National Centre for Scientific Research. “But they are extremely clever, and domestication didn’t make them stupid, but made them really capable of reading us and communicating with us.” The team from the Muséum national d'Histoire naturelle (MNHN) in Paris speculates that this could have been the reason for their temperament changes.

The researchers studied 207 skulls, 185 from modern dogs, dingos and wolves, and 22 prehistoric ones, and used CT scans to create virtual impressions of skull cavities considered a reliable indicator for skull size. While domestication began 15000 years ago, the ice age dog shows no signs of reduced brain size, but the shrinking occurred in the Neolithic era, when humans started to settle in farmlands.

Researchers argue that as humans settled in their farmland, dogs saw a change in their role, from complex thinking to more reaction-driven and instinctive responses. They adapted to the role of “living alarm systems” and scavengers, with a more wary and anxious reorganisation of their brain. Dogs that were docile and reacting in alerting settlements were preferred specifically by humans. This artificial selection of species preferred useful breeds that were capable of complex social interactions. A similar pattern is also observable in other farm animals, however the extent to which the change in brain size affects animals' intelligence is still an open area of research.

Source: WION