Science has long shown that intelligence is directly related to brain size....see, chimps, apes.....or dolphins, whales...
So why then isn't a Great Dane 100X smarter than a chihuahua?
It is not the absolute size of the brain but the size relative to the overall mass of the animal.
It’s more brain size/body size ratio that’s more important.
Otherwise Whales would be smarter than humans.