Sheldon Allan Silverstein - If I Had A Brontosaurus

If I had a brontosaurus
I would name him Morris or Horace;
But if suddenly one day he had a lot of little brontosauri
I would change his name to Laurie.

Sheldon Allan Silverstein

http://www.poemhunter.com/poem/if-i-had-a-brontosaurus/