A bottlenose has exhibited "the most durable social memory ever recorded for a non-human."
The guy on the right? He's cool. But do not mess with the dude on the left. (Shutterstock/eZeePics Studio).
Say that, in 1993, you were at a bar having some beers with a dolphin. Say that the dolphin said, "I've got the tab," and you said, "Okay, thanks -- I've got the next one." Say that you proceeded to forget about that promise, and that -- not because you didn't like the dolphin, or anything, just because life got in the way -- you never saw the dolphin again. Now say that, this morning, you ran into the dolphin, at the bank or in a tank or in the pool of some terrible resort in the Bahamas.
Here's the awkward thing: The dolphin may well remember you. And maybe the debt, too.
For the rest of the story: http://www.theatlantic.com/technology/archive/2013/08/if-you-insulted-a-dolphin-20-years-ago-hes-probably-still-bitter-about-it/278446/