Question

Why does a wolf have a brain so much bigger than that of a poodle, when a poodle's brain is big enough to do the job, I would have thought. Likewise, if tigers are not smarter than house cats, why do they have brains that are so much bigger? Brain tissue is metabolically expensive, and so you'd think there would be a strong selection pressure to have the smallest brain that could do the job.

I'm familiar with the idea that a large body needs a large brain to control it, but I've never understood why that should be the case. And since poodles are modified wolves, it should be easy for wolves to quickly evolve poodle brains in nature. Has anyone tried to create a large breed of dog with a small brain, to see whether it's possible, and what problems if any the animal has in controlling it's body, for example?

So my question is: Why do animals with more mass tend to have brains with so much more mass when it seems like a similar mass brain should be able to do the job?

Answer 1

A small brain probably wouldn't be strong enough for a larger body

Answer 2

Mammals, including dogs, have larger brains for their body size compared to other vertebrates. The size of the brain is influenced by factors such as social behavior and intelligence. The larger cerebrum in intelligent mammals allows for higher intelligence and complex social interactions.

Step-by-step explanation:

Compared to other vertebrates, mammals have relatively large brains for their body size. The size of the brain in mammals, including the different breeds of dogs, is not solely determined by the size needed to perform basic functions.

It is also influenced by other factors, such as the complexity of social behavior and intelligence. Researchers have found a correlation between the surface area of the cerebral cortex and intelligence in mammals. This increased surface area is achieved through increased folding of the cortical sheet.

For example, animals with higher intelligence, such as chimpanzees, humans, and dolphins, have a larger cortex with more sulci and gyri compared to animals with lower intelligence like rats.

The larger cerebrum in intelligent mammals allows for the development of higher levels of intelligence and the ability to learn new behaviors. It also enables complex social interactions. While large brains are more metabolically expensive, the advantages of intelligence and complex behaviors outweigh the costs for these species.