I did these in January with my grade ones. I got the idea of making the sharks from Look at my Happy Rainbow . To make them musical and to reinforce grade 1 rhythms, each student had to write a 4 beat rhythm using ta, ti-ti or rest inside their shark's mouth! After they were finished, we clapped each of the shark rhythms together as a class.
I woud like to do the rhythm sharks again next year, but I think I will use construction paper rather than having the kids colour paper plates. That might look better!