To arrive at this observation, these scientists, including a paleontologist from the University of Zurich, measured the size of 13 skulls of aurochs, the ancestors of common cows, preserved in various European museums. He then did the same with the skulls of hundreds of extant domestic cows or bulls. results published in a journal of 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 seen in pigs or companion dogs, but this is the first time that a study has looked at cattle. The question is why a decrease in the area of the brain that controls fear and aggression, two factors that all of these animals typically get rid of, over generations, when exposed to males.
In addition, Swiss scientists have realized that the size of the skulls of extant cattle also differed depending on the amount of time spent daily with the males: thus, the skulls of bulls raised for bull fighting, often semi- Grows in freedom, remains greater than its progenitor raised for meat (or for its milk, if we speak of cows).
Presence with males also has an effect on whale size. 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 length of one meter compared to those born in 1981. In question, many stress factors are associated for example with the presence of fishing nets in which these mammals may find themselves trapped, collided with ships or increased marine traffic that would disrupt the food chain.
These are all conditions in which the animal must expend more energy for its survival than before, which according to scientists would leave less reserves to ensure its maximum growth.