One of the reasons I bought my HHR was because it was pet friendly and had room in the back. I have a Golden Retriever that is about 78 pounds and she has no problem fitting in the back even with the rear seats up. On occasion, if it is just me and my dog, I will lay the rear seats down to give her extra room. I also use a blanket to protect the rear bumper cover from scratches. To help keep her from jumping over the rear seats, even though I know she wouldn’t, I use a soft Net Barrier made by Solvit (got it for around $35). I also got an extra set of attachment for when I want to move it to behind the front seats.