It could be that PB's just young. I'm going with that theory, since it's the one I can work with. I've been cultivating his acquaintance, establishing my character as Nice Human With Lettuce. He's still twitchy, but he's learned the "come here, I have a snack for you" noise. I've moved him to the old CritterTrail cage so I can get hold of him more easily. PB initially foiled this plan by moving his seeds and bedding up to one of the observation areas, from which he could instantly jump down and hide in the access tube. You'd swear he had bat in his ancestry. He's perfectly happy hanging upside-down in his tube, eating sunflower seeds from his seed stash in its bottom right-angled curve.
PB's antics in the tube were fun to watch, but he wasn't getting socialized that way, so I temporarily put domed stoppers over the bottoms of his two access tubes. This limits him to the main cage area. He's rejected the little dome-shaped hamster house I gave him, and instead has bermed up his cage litter and dug a foxhole in the corner under the wheel, with a thicket of paper towel strips stuffed in above it. He makes little noises while he works on it.
That's one of the weirdest things about Porco Bruno: he's vocal. Most hamsters are silent, or nearly silent except for an occasional squeak of dismay. The day I brought him back to Tor from the pet shop, he expressed his displeasure by I-swear-to-ghod roaring -- sounding, as our intern Torie said, either like bad plumbing, or an extremely small velociraptor. He hasn't roared much since he got here, I assume because he's never been that upset again. But he continues to express himself with a wide variety of squeaks, growls, peeps, chirps, and other strange sound effects.
Yesterday afternoon, when I was working at home and he was curled up asleep in his nest, he suddenly let out a seriously distressed hamster-scream, followed by a series of loud squeaks. I went over to see what was the matter and found him hazily thrashing around, feet-up, obviously half-asleep. I cupped my hand around the corner of the cage and held it there so his nest would be dark and warm, and he soon went back to sleep.
I know hamsters dream; all mammals from the marsupials up exhibit REM sleep. Besides, I held Arthur while he was sleeping during his final illness, and he was definitely going in and out of dream sleep. What I want to know is, do hamsters have nightmares? Because that's exactly what this looked like.