monkeys and bananas

This morning Lincoln was fascinated by the vein in my hand. 

 I told him that there was blood in it, and he tried to "listen to the blood."  

Alas, he did not hear anything.

Brent advised him to put his head on my chest, so that he could hear my heart pumping blood.

"Did you hear mommy's heart beating?"

"Yes.  I hear-ed it."

"What did it sound like?"

"It sounded like bananas or monkeys."

"What do bananas sound like?"

"OO-OO AH-AH  OO-OO AH-AH"

"That's what mommy's heart sounds like?"

"Yes."

Thank you Doctor four year old.