[otto]

The cage you have is roughly 620sq inches meaning cage aggression could definitely occur if you have a demanding hammy. I agree with above. Leave him alone for a while. Then i’d begin taming right from the beginning: talking, then treats from hands, treats on palm of hand, bathtub bonding etc. My boy started teeth chattering when I started to spot clean the first time but he immediately cooled down.

If he doesn’t get any better and starts display more stressed behaviour, such as pacing back and fourth, monkey barring etc. you might want to try him in a bigger cage and see if it helps. Luckily you have a dwarf and they are known to settle down in cages of about 800sq inches so you definitely have routes to approach if things don’t get better. Good luck!