Horses Don't Sing?

My kids have never truly listened to kid music.  Even when they were very small, there was little Barney, or Sesame Street, or Kids Bop, (for the safety of my children, we will NEVER own Kids Bop - it makes me edgy!) or anything else of that nature.  We usually have a homemade CD mix that we play over and over, memorizing most of the lyrics, and the kids asking me to play the same one or two songs 80-zillion times.

Some of the currant favorite songs are Lady Gaga - "Born This Way" (blech), Colbie Caillat - "I do", and Jason Aldean - "My Kind of Party."

So Nathan and I are driving home a little bit ago, and he is singing along with Jason Aldean.

"Got the cover off the '68,
Fired it up and let them horses sing"

And it suddenly occurs to him that it doesn't make sense.

Nathan: Mom, did he just say "fart it up" (has that really been what he has been singing this whole time?)
Me: (trying not to laugh) No, buddy.  He is saying fire it up.  That means he started up the truck.
Nathan: Oh. But Mom, Horses don't sing.  Birds do.

At this point I am openly laughing and trying to explain to my 4 year old that there is actually logic to that sentence.  I am still not sure if he got that horses means the engine and sings means the way it sounds. 

I so LOVE his literal thinking!  It is still making me smile.