21. Is it the weather, or evolution, or brain size , or avaliable resources? 22. Attempts to support these theories cited'scientific evidence', such as brain size . 23. One question that has been frequently investigated is the relation of brain size to intelligence. 24. Recent studies have shown that birds are pretty intelligent, despite their small brain size . 25. But it is still unclear why the number of IQ domains should correlate with brain size . 26. Studies demonstrate a correlation between brain size and intelligence, with larger brains predicting higher intelligence. 27. :Generally body mass correlates with brain size ( see brain to body mass ratio ). 28. Its brain size is about 850cc. 29. The greater size of the skull cavity overwhelmingly implies a greater brain size and exceptional intelligence. 30. "The increase of brain size relative to body size encephalization is intimately linked with human evolution. 