Mouse over Doesn't work

I tried to test the power of mouseover.
In this case when you mouse over the skull of my skeleton it would change the scale of the skull so users would know the mouse is over that figure…
but it doesn’t work and I’m baffled.

http://www.fileconvoy.com/dfl.php?id=g669bfef962bed20899938744876ea65f6afe4d063