The white parts of the costume are made out of fleece. The tail is black faux rabbit fur, and the whiskers are made out of pipe cleaners. You can see that the whiskers got progressively curlier the more it was worn. I only wish I'd gotten a better photo of the tail! Thanks for looking!
The pattern I used can be found here: http://projectsbyjess.blogspot.com/2007/01/woodland-animal-costume-sewing-pattern.html