[Ria P]

There's another trick i've read about here.

Let your hamster go into a glass jar and lift him up to check his underside. You may be able to tell the gender.

I have a dwarf who looks like yours and bites my hand but takes food from my fingers. I made him a playpen from a Xmas tree box and get him in and out of his cage with a mug he walks into.

Like Vierville said, they are prone to diabetes, in fact, my dwarf has diabetes which i suspected soon after adopting him. He drinks and pees a lot and was quite aggressive but has calmed down a bit with a better diet and housing.

I feed him the Rodipet Hybrid mix and add extra protein with mealworms and occasional boiled egg. Avoid fruit, honey based sticks, carrot, dried fruit etc and give him greens like kale, spinach, broccoli etc. Mine loves cucumber. I give him seeds for a treat like linseeds and pumpkin seeds. Best introduce fresh food slowly if he's not used to it.