That's like my dog and my brother's guinea pig. My dog is a miniature schnauzer, a bred ratter dog. He is a purebred and in the past this breed was made for digging down in rat(any rodent) holes and pulling them out. So, not much difference in his eyes between a rat and a guinea pig. He is becoming more accustomed to it though, they both seem to like one another now.
Q. What's brown and sticky? A. A stick!