Well.. Africa isn't too far from Greece... and seeing as the story involves gods and stuff, I'm certain they could make some of the snakes in her hair pythons with inch long fangs. I've never had to opportunity to examine the rare subspecies of medusa ball python.
Yeah.. I recently was harping about the robots in Transformers 'crying', and the realized I was saying that the crying was not very realistic in a movie filled with giant transforming robots from another planet involved in a war with evil giant transforming robots, all of which decided on Earth as the mudball to land on.
Suddenly it didn't seem so wacky. Now, when they make GI JOe/Transformers, it'll be giant transforming robots with NINJA!!!!! They'll advertise it as "Now try our New Improved movie with added Ninja for coolness!"