The average weight of a chimpanzee brain is 384 grams (13.5 ounces); our brains are three and a half times heavier. That’s only part of the story though, because different species have different brain structures. Rodents’ brain cells, for example, are much less efficiently packed and for a rat to have the same number of brain cells as us, it would need a brain at least 35 times larger than ours. However it seems that chimps are close enough relatives that they have similar brain structures so they do actually have about three and a half times fewer brain cells than us – at roughly 49 billion. Chimps have less brain dedicated to white matter in the temporal cortex, which means they have fewer neural connections and so a lesser ability to process data.
Answered by Luis Villazon