Living with humans shrinks cats' brains, new study finds

A new study has revealed that thousands of years of living with humans has seen cats' brains shrink "significantly".

The study, published in Royal Society Open Science, compared the craniums of domestic cats with those of their closest ancestors, African wildcats.

"Our data indicate that domestic cats indeed, have smaller cranial volumes (implying smaller brains)," the study authors wrote.

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The numbers showed domestic cats craniums were up to 25 per cent smaller than their wild cousins.

But cats aren't alone, with the researchers noting similar traits in other domestic animals, including dogs and rabbits.

Even livestock such as sheep, have suffered a similar reduction.

"Reduced brain size, compared with wild individuals, is argued to be a key characteristic of domesticated mammal species, and often cited as a key component of a putative 'domestication syndrome'," the researchers wrote.

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The reduction is attributed to a deficiency in neural crest cells, which develop in the embryonic stage and contribute to a wide range of bodily developments.

"Selection for tameness in the domestication of animals may have caused a downregulation in the migration and proliferation of neural crest cells, leading to decreased excitability and fear," the researchers wrote.

"However, this downregulation may also cause correlated changes to morphology, stress response and brain size."

Although the implications are not overly dire for housecats, the researchers pointed out that hybrid wildcat-housecat crosses were also born with smaller skulls, leading to the need for further research on whether this presented a danger to wild animal populations.