Boy gerbils actually do have nipples but less visible then female and seem to be less in count having a possible four.
Yes. I have to boy gerbils and they both share there water.
yes. well sometimes they do.
To be honest, if you just buy 2 gerbils, boy and girl, then it is unpredictable to know when they mate. They could mate anytime. :D
two boy gerbils should not fight, aslong as they knew each other form since they were pups. if not, use the split cage method and you should be fine. if you leave some old bedding in the cage when you clean it out gerbils are less likely to fight. girl gerbils are more dominent so boys are less likely to fight then girls. always keep a pair of gerbils, or they will get depressed. some gerbils do like to live alone, but this is uncommon.
yes but only if you are expecting baby gerbils.
Ask a vet
Males are typically calmer and less territorial than female gerbils. But with any gerbil, if it is not already a cagemate or sibling, it must be introduced properly through a split-cage method. You can find many examples of how to do this at: http://homepage.mac.com/kyleekay/tip-of-the-week/tip072003.html or http://www.twinsqueaks.com/split-tank.html Hope this helps.
It depends on their nature. Some are more aggressive than others so you might be careful aroud them. If you are looking to buy one, just look at its behavior and that will probably tell you if they bite or not.
All gerbils have a pinkish thing, that being their reproductive system, and a darker circle, which is their butt. The dark one is closer to the gerbil's tail .You can find them on the gerbils' underside. If the pink and dark holes are closer together, your gerbil is a female. If they are further apart, you have a male.
Other gerbils.
Gerbils are an animal and can not be "invented".
Male gerbils can be neutered, but it is not recomended. Female gerbils should not be spayed. In general male gerbils should not be neutered unless there is a good reason for it.