A squirrel is sitting up in his tree, happily munching on an acorn. When suddenly, he looks up to the higher branches of the tree.

He sees a cow up there.

"Cow," he asks, "You don't belong up here! What are you doing up in my tree?"

"I'm eating apples, the cow says.

"But.." the squirell starts, "This is an acorn tree."

"Yea," says the cow, "I brought my own."