New hamster chewing / climbing bars

[bronzino]

Hi all,

Sorry if you get this question a lot but I've got a new Syrian hamster, I've had him for 4 days and I've noticed he's started chewing the bars of the cage and occasionally bar climbing. He's in a 100x50x50cm cage recommended by the pdsa, his bedding is nice and deep and he has lots of toys, hides and a 33cm wheel which he runs on a lot! Before buying him I was asked to supply pictures of setup and the breeder was very happy with the home. He's showing no signs of ill health, he eats and drinks properly and has made a nice nest in the substrate for himself so I don't think he's physically ill.

Is this just a stress response to his new environment? I hate seeing him chew the bars, I don't want him to injure himself and just want him to be happy!

Thanks in advance!