We thought that domestication shrank dogs’ brains forever. Now we know we were wrong
When the first wolves began to approach human settlementsthey signed an evolutionary contract that would change their species forever. They gained easy food, warmth and protection, but in exchange they had to give up their brains, which have been reduced in size since we began to domesticate them, as science has pointed out. But this is changing now. From more to less. that the animals domestic have smaller brains than their wild ancestors is something already well known, but the “when”, the “how” and above all the “why” of this phenomenon were between two questions. But now a new study published HAL Open Science has managed to put a key date on this transformation, revealing that the brain “shrinkage” of dogs was already fully established in the late Neolithic. How it has been seen. To understand what happened inside the head of man’s best friend, the team of researchers did not limit itself to measuring the skulls with a tape measure, but used CT to analyze 22 prehistoric skulls dating from the Mesolithic to the late Neolithic in Western Europe, comparing them with 185 modern dog skulls, and using as a reference a 3D model of a wolf skull from the 19th century. The results. Here they were quite forceful when they saw that the Neolithic dogs already had an amazing 46% reduction in volume endoraneal compared to wolves. According to the data, these prehistoric French dogs had what we could call “miniature brains”, as a consequence of undergoing an evolutionary adaptation to new roles in agricultural settlements. And, by not having to hunt in nature, defend vast territories or be on constant alert against predators, the parts of the brain dedicated to extreme survival, which consume a lot of energy, simply ceased to be necessary. There are more culprits. Although this story sounds perfect, biology is more complex and that is why domestication is not the only factor highlighted here. Here, at do phylogenetic analyzes Comparing dogs to other wild canids, scientists found that older dog breeds fall within the “normal” brain size ranges expected for their body size. In fact, they suggest that there are ecological factors that can cause brain reductions even greater than domestication. The best example here is the raccoon dog, whose brain experiences drastic reductions linked to its hibernation periods to ‘save energy’. The script twist. If the story ended in the Neolithic, we would have an animal with an increasingly smaller brain without any type of limit. But here a recent study suggests that the modern dogs bred in the last 150 years They have relatively larger brains than their ancestors. That is, the downward trend has reversed. To understand this, we must keep in mind that humans have stopped using dogs solely as basic guardians or shepherds, and have begun to require them to perform more complex cognitive tasks, such as obeying orders, assisting humans with disabilities, drug detection, and other functions in our society. And it already shows. This has not only changed the size, but also the internal architecture of the brain, as seen in the MRIs performed on 85 dogs of different breeds that revealed abysmal differences between “primitive” and modern breeds. For example, dogs that are trainable have a much larger cut, and it makes sense because this is the area responsible for learning and decision-making. On the contrary, the most primitive and ancient races retain an expanded amygdala, which is the region linked to the processing of fear, instinct, and rapid survival responses. Some qualities that are essential to be able to hunt and respond to any type of threat. Images | Pauline Loroy In Xataka | We have been using our pets to relieve our anxiety. And now the stress is on them
