If you've played a druid then I have no idea how you can not know this. They have night-elf ears because the ears is a part of the elven that stays through the transformation, as with the lions that get horns. The newly updated skins look better anyhow.
http://thepriorart.files.wordpress.com/ ... -forms.jpg
http://www.wow-europe.com/shared/wow-co ... en/ss4.jpg