Well, he appears to be leaning Scooter towards the camera, so that may cause him to look bigger than he actually is?
I don't know, but it's rather surprising (and we even have a thread about this too) when you find out just how big, or how small, certain puppets actually are, when they really don't seem that size on screen. Like the Jim, Frank, and Jerry Muppets appear to be only slightly bigger than some mini-AMs (like Prairie Dawn, Roosevelt Franklin, etc.), but then Fraggle puppets appear to be rather large when you see them in comparison with their performers.