Rutherers are large carnivores with grey fur, blue skin, and an enormous tail, found in 2nd and 3rd caverns.
Binturongs, are small civet-like mammals native to southeastern asia, also known as bearcat. Although different in size, they have resemblance to rutherer.
Picture of a binturong from wikipedia.
(http://upload.wikimedia.org/wikipedia/commons/a/a7/Binturong_in_Overloon.jpg)