To sign hippo, extend your pointer and pinkie fingers on both hands, and open and close them, having both hands meet in the middle, like a hippo's mouth.
Another ASL sign for hippo is similar except it uses the thumbs instead of the pointer fingers, along with the pinkies, of both hands.
Use the hippo sign to expand your toddler's knowledge of animals commonly found in the jungle.
We use this sign for play or when we visit our local zoo. We also reinforce it when singing the jungle song.