A new study confirms that as cats have been domesticated over the past 10,000 years, their brain sizes have shrunk significantly. This finding could lead to important new insights into how animals adapt when they are regularly cared for by humans.
The researchers measured the size of the cranium (skull excluding the mandibular bone, which is an indicator of brain size) in domestic cats.Felis catus) Were compared with feral cats in Europe and Africa. It has been genetically proven that feral cats in Europe and Africa are ancestral species, and domestic cats are actually evolved.
The researchers also examined hybrids of wild and domestic cats and found that their brain size was between the measurements of the other two groups. This result also shows that domestication causes these changes. Researchers explain in their new article:
Our data show that domestic cats compared to European feral cats (Felis silvestrisAnd the wild ancestors of domestic cats, namely African wild cats (Felis lybica), Have a smaller skull volume, which indicates a smaller brain and confirms older results. We also found that the skull volume of hybrids of domestic cats and European feral cats is located between the skull volumes of two parent species.
Cat brain size is something that researchers have been looking for since the 1960s and 1970s. Brain shrinkage has also been observed in domestic animals such as sheep, dogs and rabbits.
Researchers say the choice to be tame leads to the production of fewer neural stem cells in animals, which is associated with irritability and fear. This in turn can cause changes in stress response, brain size and overall body morphology.
The size of the roof of the mouth (palate) was also assessed, but no significant difference was observed between domestic and wild cats. There has been debate that reductions in neural stem cells should lead to shorter snouts as well as smaller cranium sizes, but these were not observed in this data set.
Although the findings of this study are not entirely new, they update research that in some cases is decades old and provide new data to scientists working on domestication theories. Researchers write:
Brain size comparisons are often based on ancient and inaccessible scientific work, and in some cases comparisons have been made between domestic animals and wild species that are no longer thought to be the ancestors of the domestic species.
One suggestion that the study authors disagree with is the claim that cats are semi-domestic compared to dogs. A view according to which cats themselves prefer to be with humans; Therefore, they cannot be considered completely domesticated.
The study notes how cats have proven useful on farms and ships in the past, and that they have more contact with people than cats who are simply looking for an easy source of food. According to researchers, domestic cats continue to be selected as pets based on their temperament, which makes them a good choice for domestication.
Finally, the researchers say, more data needs to be collected on several species to fully understand what domestication has affected cats, including their brain size, and the limitations of the information gathered so far have limitations. Scientists explain:
We must always acknowledge that we are comparing a population of wild animals to a domesticated form that is not necessarily a real ancestral population. This will always be a confusing factor; Because we rarely have access to the ancient population that our domestic animals produced. Ancient DNA, however, can improve this somewhat in genetic comparisons.
The study is published in the journal Royal Society Open Science.
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