Candy
From PinataIsland.info, the Viva Piñata wiki
What would Piñatas be without candy? The candy in the piñatas is different. Piñata love eating candy and every piñata in the game has a distinct candy themed after the animal, so the bee’s candy is bubblegum for example.Other Piñatas want to eat other piñata’s candy. They break it open and snarf it down. The broken piñata then reforms and leaves your garden because it doesn’t have any candy left. Then there are also the bad piñatas, called sours and they’re full of bad candy...you don't want your piñata to eat that candy.