Lupin and Bunny playing

Despite what may appear, these two are best friends. They play together like this everyday. Lupin, the dog, is around 30 lbs and 8 months old. He befriended Bunny almost instantly. Lupin was a stray (possibly dumped) that appeared in our yard around Halloween, and despite all efforts to locate his family by means of local rescue groups, vets, and posters, none came forward. (He is my first dog. I've owned rats off and on for over 30 years, and consistently for 15.)
 
Bunny recently lost her only remaining cagemate (an elderly aunt) and lost her littermates at a young age to heart disease. She does not like the other rats and gets territorial if any introductions are attempted. She runs to the cage door and hops back and forth in anticipation of greeting her doggy pal.