by Doctor Science
Pursuant to a dinner-table discussion, I found myself at a Yahoo!Answers discussion of "What is the most intelligent horse breed?". The consensus of the horsey people answering was (a) it depends, but stereotypically (b) Arabians. The discussion was very interesting, and included some good stories:
budrock1: I've got an Arab mare and a Morgan gelding and I'd say it's a toss-up. My Arab picks up things very quickly and you really only have to show her anything once. However, my Morgan learned how to open the automatic fly sprayer in his stall, pull out the spray can and close the door again so that I didn't know he had removed the can [emphasis mine]I've known dogs and cats who were pretty smart, but none who thought to close the door behind them.
katdncswthdog: Shetland ponies are the only horses I know with a good sense of humor...we had one that would sneak up behind you then gallop in place. When you jumped & ran I swear he'd laugh at you.So, join in with your smart-animal stories, or whatever.