This herd of cute guinea pigs at the Chiba Zoological Park in Japan has a really cute trick they do. Someone rings a bell (which I guess is what they take as their cue to start), and they all start lining up, single-file in the cutest piggy parade!
I couldn't find much info, but it looks like these guinea pigs are part of the petting zoo there. There's a diagram below the video of the other animals in the children's area. It was too cute not to share, too!
Click to biggify!