The Manatee by Jack Prelutsky
found in A Pizza the Size of the Sun
(Greenwillow Press) page 61
I have put in some key words to show how the words fit in with the music. It's a good beginner piece for teaching the Orff instruments as the parts are fairly easy. You can always add more, or if you don't have Orff instruments, it can be played on Boomwackers.
I found my GA students didn't know much about Manatees (unlike my FL students), so this is a good chance coordinate your lessons with the classroom teachers about endangered species, or just about the Manatees.