Arthur - Series 14 - Whistling in the Wind

Animation. Join Arthur, possibly the world's most famous eight year old Aardvark, his sisters DW and Kate, and some of their many friends Buster, Francine, The Brain, Muffy, Sue Ellen, Fern, Prunella, and Binky as they encounter the joys and difficulties that all children experience in their adventures through life. Based on the popular children's books by Marc Brown. Everyone knows the Tibbles are exactly the same. They look the same, they act the same, they even have the same number of hairs on their heads. So if they are supposed to exactly the same, why can Tommy whistle while Timmy can't? Does this mean one twin is better than the other, or just different?