Elephants have the largest brain, nearly 11 pounds on average of any mammal that ever walked the earth. Do they use that gray matter to the fullest? Intelligence is hard to quantify in humans or animals, but the encephalization quotient (EQ), a ratio of an animal’s observed brain size to the expected brain size given the animal’s mass, correlates well with an ability to navigate novel challenges and obstacles. The average elephant EQ is 1.88. (Humans range from 7.33 to 7.69, chimpanzees average 2.45, pigs 0.27.) Intelligence and memory are thought to go hand in hand, suggesting that elephant memories, while not infallible, are quite good.