Immaculate Hamster Conception

Question
Hi,

My girlfriend called me over today to check on her hamsters.  The one that she caught in the act, as detailed in a prior question, doesn't show any signs of pregnancy, although she still has a few days before we're out of the woods with her.

However, another one was acting strange last night and she wanted me to take a look.  Right above her hips area was a large, solid bulge.  At first I thought it might be a cyst or a tumor.  But then I noticed it was uniform.  And then I felt something in that bulge bite or kick me.

Sure enough, tonight this hamster gave birth.  We don't know how many babies there are going to be this time.

Now this is where things get weird.  This new mommy hamster hasn't been in any position to mate with any of the 4 adult males in the room.  They're all in separate tanks, with lids.  Only one of them has shown any ability to escape, but he's unable to lift the lid of a tank when he's on the outside.  There are no holes in the roof of her aquarium.  It seems impossible!

There are only a couple of ways that this might have happened, as far as we can figure.  First, all the hamsters get to run around the room.  However, it's always just the girls from a litter or just the boys.  My girlfriend keeps the same-sex members of the families familiar with each others scents and they don't fight when roaming around her room, as it's become neutral territory.

I'm not sure what the life of hamster sperm is, but if some was left on the carpet of the room and the new mother sat on it could that have done it?

The second way that we're guessing at is that one of the boys was on top of her cage and somehow sprayed down in on her.  Again, very slim possibility.

Another, even more ludicrous way was that the new mother was sitting on top of one of the boy's cages and he climbed up his water bottle and hung upside-down on the wire mesh roof of his cage to do the deed.

I don't think that this was an immaculate conception.  But it sure sounds like it.  What we really want to know is two things.

1. How the heck did this hamster, who had no visible, possible contact with any male hamsters get pregnant?

2. How do we prevent this from happening again?  It's kind of exciting to have a mystery on our hands, and baby hamsters are really cute, but these are going to have to go.  My girlfriend already has 12 hamsters and her formerly large room is now covered in aquariums and the smell, especially on days when more than one girl is in heat, is terrible.

Answer
Hi Robert

This really is a mystery.

I have read articles about dwarf hamsters who have delayed impregnation - this sometimes occurs in the wild when a pair have mated but as the circumstances aren't good for a litter to be born (due to severe weather, lack of food etc) the female can delay the pregnancy.  However I have never heard of it in Syrians, and certainly not in captivity.  

At some stage she must have come into direct contact with the male.  Mating can take literally a second and at some stage (no idea how if they are kept separate) he must have got close enough.  Female hamsters can go very rigid when in season when they smell a male and perhaps she did this up against the bars of her cage and he was climbing on the outside bars and managed to impregnate her then.

It sounds as though your girlfriend is getting over-run a bit with her hamsters and perhaps with this new litter it might be an idea to see if you can get some help.  Do you have a local pet shop who will take the litter when they are 4 weeks old?  Is there a local pet rescue that you could contact and ask them to take some of the hamsters away.  I love hamsters (and in fact all animals) and in the past I have had a lot - the most at one time was 37 and I had cages everywhere.  However, over the years I have found that I can give so much more love and attention to my hamsters if I only keep a few.  At the moment I have 4 hamsters, 2 gerbils, 3 guineapigs and 2 rabbits.  In addition to these I foster hamsters for a pet rescue and then return them a few weeks later when they are ready for re-homing.  This number of cages seems to work well for me and I no longer feel the situation is out of control.  It has also cut down dramatically in the amount of time I have to spend cleaning out, the cost of all the bedding etc, and possibility of smell.  It is a hard decision to make but perhaps with the arrival of this litter this is a good time to take steps to try and get some help.

Sorry if I sound as though I am preaching or telling you what to do - I don't mean to.  I am just sharing my own experience.

I hope this helps you.

Regards
Sheila