There are theories, not generally accepted in mainstream biology/anthropology. One is that our ancestors lived in coastal areas, where seafood made it much "ch

There are theories, not generally accepted in mainstream biology/anthropology. One is that our ancestors lived in coastal areas, where seafood made it much "cheaper" (in the evolutionary sense) to obtain the kind of fatty acids needed for growing a bigger brain. https://www.psychologytoday.com/blog/lives-the-brain/201001/was-seafood-brain-food-in-human-evolution https://www.psychologytoday.com/blog/lives-the-brain/201001/...