The teddy bears have been looking forward to April Fools' Day this year so that they can prank each other with mischievous jokes. But why is April Fools' Day a specific day to do that? It has been celebrated for centuries in many parts of the world. And many historians (that's people who study history) believe that it all started with just a calendar change!
In 1582 (a long, long time ago), France switched from the Julian calendar (which celebrated the new year in Spring) to the Gregorian calendar (which marked the beginning of a new year on the 1st of January instead). Some people didn't learn about this quickly enough and continued to celebrate the new year during the last week of March instead and were laughed at and pranked for it.
