The short (and only) answer is no.
No to girl/boy combo’s, no to girl/girl combo’s and definitely no to boy/boy combo’s.
Syrians are incredibly territorial creatures – they will fight to the death if another hamster is sniffed out. Basically the thing to remember is that Syrians are solitary animals. Even when you have a boy and girl hammy they can’t be kept together for more than 15 minutes even when you want to breed them! Girls will get very impatient and nasty towards the boys and you certainly don’t want to be the one to split up fighting hamsters (and that’s experience talking!)
There really is nothing worse than 2 squawking hamsters biting and clawing at each other in a fuzzy ball of anger – like the fighting dust balls that you see in the cartoons, but nowhere near as entertaining!
As readers of this blog will be aware, I am an owner of three Syrian hamsters, 2 boys and 1 girl. They each have their own cage, their own exercise ball, their own everything! The scent of another hamster is very agitating for them so it’s important to keep things separate.
Eve leaves her smell everywhere anyway so it more of a tease for the boys. But this is manageable. It doesn’t offend any of them, it just gets them all hyped up.
When Dexter smells Casper, or visa versa, problems can erupt. I can end up with two very grumpy, very hissy and very vocal hamsters on my hands! On the very rare occasion that both boys are out at the same time, I will hold one and the boyfriend will hold the other. But as soon as that scent reaches the other Dexter will seriously wriggle about to free himself (gears himself up for a fight – little does he know Casper is twice the size of him!)
The other day both boys were out and I ended up with Casper crawling on my lap and Dexter sat on my chest. There was a very tense moment or two when they seemed to clock each others presence and I had a challenge on my hands keeping them in separate places. As you can see from the picture, Dexter was very wary of something else sneaking about in the background but played the silent, waiting game instead of the charge into things like a looney game.
I put Casper back in his bed and waited until Dexter had been given enough attention. Letting them actually greet each other would only end in injury and there is no need for such things. Especially as they are both young, healthy hams and giving them even half a second of opportunity should end disastrously.
Note to all Syrian owners: Do not let your Syrians meet! They love your attention, not another hamsters!