I'm sure the left one is negative since all the hairs stand up meaning they are attracted to the earth with has a positive charge, like static hairs. The right one must then be positive, since it's like the earth - brown, flat and round.
Love this character. Also love the still image from the animation that's in your description. Just that little poof at the end of the tail is also really cute! Your knack for creating unique and adorable creatures is seriously enviable.