Dolphins can remember and recognize old friends that they haven’t seen in 20 years! This is even more than human’s ability to recognize and remember other humans’ faces they’ve seen before. How do they do it? Each dolphin has an unique whistle signature that identifies it. These whistle signatures never change and are used for precise recognition. This is a better method than human’s because we recognize each other by our facial features which change through time. A recent study has showed that even after twenty of years of being apart dolphins are able to recognize the whistle noise of a old friend.