To arrive at this observation, these scientists, including a paleontologist from the University of Zurich, measured the size of 13 skulls of aurochs, ancestors of common cows, skulls preserved in various European museums. They then did the same with hundreds of current domestic cow or bull skulls. Results, published in a journal of the Royal society, the British equivalent of our academy of sciences: the skulls and therefore the brains of today’s cattle are 26% smaller than those of their distant ancestors.
This is also an effect already observed in pigs or companion dogs, but this is the first time that a study has looked at the case of cattle. What is in question is the reduction in the area of the brain which regulates fear and aggression, two factors that all of these animals generally get rid of when they come into contact with men, generation after generation.
Moreover, Swiss scientists have realized that there was even a difference in the size of the skulls of current cattle depending on the time spent daily with men: thus, the skull of a bull raised for bullfighting, which often grows in semi-freedom, remains larger than that of its congener raised for meat (or for its milk if we speak of cows).
Attendance with males also has an effect on the size of whales. In a study published in June in the journal Current Biology, American researchers have shown that North Atlantic right whales born in recent years have lost a maximum of one meter in length compared to those born in 1981. In question, several stress factors linked, for example, to the presence of fishing nets. fishing in which these mammals can find themselves trapped, collisions with ships or the increase in maritime traffic which would disrupt the food chain.
These are all situations in which the animal must spend more energy than before for its survival, which according to scientists would leave it less reserves to ensure its maximum growth.