The reason that pets often have reduced brain

People have domesticated many animals such as dogs, sheep and horses. Nearly every pet has a general change in the body, that is, the brain shrinks.

The duck's brain shrinks about 15%, with cats being 30% and pigs up to 35%. even farmed salmon has a brain smaller than 20%.

This is quite strange because in general, brain size and animal body size are closely related.

Brain size and animal body size are closely related.

Dust mites have a smaller brain than ants, the brain is smaller than a rat's brain, the mouse's brain is smaller than an elephant and so on. This relationship is also true for individuals of the same species. For example, small wolves have a smaller brain than big wolves and small dogs have smaller brains than big dogs.

When comparing two individuals with the same size of wolves and dogs, the wolf brain is always larger no matter what size the body is. Furthermore, scientists found that with different animals, there was a reduction in the proportion of brain regions that controlled information from the outside environment and informed the timing and how the reaction was panic similar to a signaling button .

In general, creatures with larger buttons will have a more responsive or fleeting reaction, while creatures with smaller buttons are more healthy.

It is possible that humans have chosen them to try to tame, by mating the most domesticated animals, humans make the signaling buttons as well as their brains shrink. Thus, pets form long-term relationships with humans while the brain is reduced.