I saw one at (I think) Disney Animal Kingdom. It seemed to be curious because it peeked into the vehicle. I was absolutely astonished at how huge the head was. They look so tiny up in the air. It was like seeing a traffic light at eye level for the first time.
A more accessible example of this effect is that your foot, heel to toe, is about the same length as your forearm, elbow to wrist.
People have real trouble believing this because your foot is always farther away than your arm is.
Very cool thing, they charge $5 for the lettuce but its worth it. I'd pay more than that to be licked by a giraffe.