An orca's brain is nearly four times the size of a human brain. Both human and orca brains contain deep folds that are indicative of the potential for high intelligence. Though we know much about the nature of human intelligence, our knowledge of the nature of orca intelligence is so far quite limited. However, there are many things about orcas and the way they live that convey a sense of their intelligence. Dr. Spong believes the fact that orcas have learned how to live peaceful lives in cooperative societies that have survived the test of time is one such sign. Of course, humans and orcas live in very different worlds, so the manifestation of intelligence in the two species can be expected to be quite different. Nevertheless, the day may come when humans learn from orca intelligence.