I'm not sure of the answer but I had a Female named carly..and I had her for about a week and she seemed so sweet and Gentle..until about a month after I got her she would Bite you if you Picked her up or even got near her..Thinking she may be Lonely I went back to my Local Pet store And got another one..this time a male..Which I named Spencer..When I got him home..I put him in the cage with her..and she never came out of her House..when she did..She attacked him and Ripped his Neck open..and I had to take him to get 5 stitches..in his little Neck.. My vet informed me that most dwarf hamsters will not get along unless they are from the same litter or was in the same cage when you Bought them..they are not very good adapted animals..and will not take Kindly to a new hamster in "their" Territory. I would say get two cages and keep them apart..and slowly let them get use to one another. Good luck Hope this helps.