Why the brain of a mammal usually is larger than other animals same size?

The brain of a mammal is usually larger than that of other animals of the same size due to several factors:

1. Encephalization Quotient (EQ): Mammals generally have a higher EQ compared to other animals. EQ is a measure of brain size relative to body size. A higher EQ indicates a proportionally larger brain for the animal's body size.

2. Neocortex Expansion: Mammals possess a well-developed neocortex, which is responsible for higher-level cognitive functions such as memory, language, abstract thinking, and complex decision-making. The neocortex is relatively larger in mammals compared to other animals.

3. Gyrification and Sulci: The mammalian brain exhibits a characteristic folding pattern known as gyri and sulci. These folds increase the surface area of the brain, allowing for more neurons and greater computational power within a smaller volume.

4. Neuronal Density: Mammals generally have a higher neuronal density compared to other animals. This means that there are more neurons packed within the same brain volume, contributing to increased cognitive capacities.

5. Synaptic Complexity: The mammalian brain exhibits a high level of synaptic complexity, with numerous connections between neurons. These intricate neural networks enable efficient information processing and underlie complex cognitive functions.

6. Evolutionary Adaptations: The evolution of mammals involved specific adaptations that favored larger brains. The need for social interactions, tool usage, and environmental adaptability drove the selection for increased brain size.

7. Visual Processing: Mammals have evolved advanced visual systems, and the brain regions responsible for visual processing tend to be larger in mammals. This is especially evident in primates and other species with highly developed eyesight.

8. Learning and Memory: Mammals are known for their ability to learn and remember, and the brain regions involved in these processes, such as the hippocampus, are relatively larger in mammals.

It's important to note that while mammals generally have larger brains relative to their body size, there is still significant variation among different mammalian species. Additionally, brain size alone does not determine intelligence, as other factors, such as brain organization and connectivity, also play crucial roles in cognitive abilities.