Actually they need a net across the middle to keep them separated! I don't know how many times I had to tell Tubby to leave Peanut alone. Now that he's in a confined space with her, he thinks it gives him free reign to lick on her all the time and poor Peanut has no place to go to get away from him. I'm sure it's just a matter of an adjustment period though, and I don't plan on leaving them alone - unattended - in it, so hopefully he'll soon get the idea and learn to leave her alone.....and gee, maybe the idea of leaving her alone will transfer to when they're in the house too. Now that would be a wonderful thing.