This game works smoothly in groups of 5 or 6. Start with having students choose an animal and a gesture that pairs with that animal. Once everyone has decided on an animal and a gesture, you can start the game. The game starts with the same beat as "We Will Rock You," by Queen. Tap Tap Clap Everyone chants in rhythm "1...2...3...Let's Play Zoo." Decide a starting person (this can be easily decided by the winner of rock paper scissors). While other members of the group are keeping the beat, the starting member will perform their own animal gesture and another member's animal gesture. In this way the starting person has passed play to the person whose gesture he/she performed. Similarly the next person performs their own gesture and the gesture of the person to whom he/she wants to pass play. This continues until one player messes up a gesture or can't play fast enough. Start the next round of the game from the player who messed up last. When the kids get used to the gestures and animals, start a new round and have them switch to a new animal and create a new gesture. This keeps the game fresh.
Here is an example of how the game works. Let's say one person has chosen a gorilla with a gesture of beating their chest and another person has chosen a bird with a gesture of flapping their arms. The person who chose a gorilla would start as such: Tap Tap Clap "1...2...3...Let's Play Zoo." gorilla gesture in one sequence of Tap Tap Clap and bird gesture in the next sequence of Tap Tap Clap. Then the person who chose a bird would do their bird gesture and then pass play to another person by doing that person's gesture.
Making the activity easier: Instead of passing play right away a player can pass play to themselves by continuing to do their own gesture. In this way, he/she gets more time to think of the other players' gestures.
Making the activity harder: Start off slow and gradually increase the speed as the game continues. Additionally you can have the students name the animal of which they are gesturing. If you want to make the game even more difficult, you can prohibit return gestures. If one player receives play from another, you cannot do the gesture of the person from whom you received the gesture.
Notes: I've never tried it, but you could probably play with other vocabulary terms. Anything that you can do gestures to is available. You could also probably try grammar structures in the game as well. For example, "1...2...3...Let's Play Zoo." In rhythm: "(starting person is a turtle) I live in the sea, (person whom play was passed to is an eagle) You live in the forest." "I live in the forest, You live in the desert."