I don't know if it's because I've been taking him out more often recently, or if he figured out that up = out, but my BP seems obsessed with the top of his cage now.
Also, there's a small space between the glass and the top of the cage. He will wedge himself in there and swell up like he's trying to lift the lid off. My main concern is that he's scratching his belly against the wire mesh top of the cage and I can hear his skin catching although he doesn't appear like he's shedding.
I just found this odd and wondered if anyone else has had similar experiences.