I thought I separated my hamsters by gender, but tonight I walked in on what I thought were two boys having sex.

They are five weeks old, so as I understand it this might even be the first time the female was "in heat". So what is the likelihood that she is now pregnant?

PS: I have already separated them now so they are all living in their own homes. These are young Syrians, so for the moment some of them are living in dwarf hamster cages - but no more chance of sex!!!

Indeed, hamsters can become pregnant at the tender age of 35 days!