We can easily say that people are the most successful species on earth. Like humans, there is no other species that has spread all over the world and has managed to dominate the area around it. The reason why people can be so successful is rightly attributed to being smarter than other species. The wrong idea is that the fact that people are smarter than other living things is connected to the size of their brains.
There is no linear relationship between the size of the brain and intelligence. Just because a person is short or even a dwarf does not mean that your brain is less intelligent. We can understand this by examining species outside of human. For example, the brains of dolphins – roughly 1400 grams – are almost the same size as the brains of humans. But even though they are relatively intelligent creatures, it can not be said that dolphins are as intelligent as humans. Whales with eight kilograms of brains are generally not as intelligent as dolphins. The brains of the orangutans, who are thought to be much smarter than the Balinese, are only about 400 grams.
What makes a living thing smarter is not the size of the brain, but the ratio of the mass of the brain to the total mass of the living thing. In an individual of about seventy kilograms, this rate is one-fifty, while in other mammalian species the individual falls by a hundred or so. In birds, the ratio of the mass of the brain to the total mass of the living thing is only about one hundred twenty.
The fact that the mass of the brain is large in relation to the total mass of the living thing allows the greater part of the brain to focus on the work requiring intellectual effort such as memory, thought, communication. This causes the creature to be smarter.
Dr. Mahir E. Ocak