The assumption is that, due to its height, the giraffe recieved a direct strike. Lightning can do some pretty wild stuff. Last night I was looking at an article on lightning safety. There was a photo in the article that showed about 30 cows that had lined up near a fence when a strike hit nearby. Due to ground conduction, all 30 or so cows dropped dead where they stood. They looked like they had been neatly lined up.