Researchers have found evidence suggesting that intelligence evolved independently in birds and mammals, rather than being inherited from a common ancestor. This indicates that complex neural circuits supporting cognition arose multiple times in vertebrates.
Ravens parallel great apes in physical and social cognitive skills - the first large-scale assessment of common ravens compared with chimpanzees and orangutans found full-blown cognitive skills present in ravens at the age of 4 months similar to that of adult apes, including theory of mind.
