Hey, I had TONS of gerbils and rodents! I got a "female" ( i was younger at the time.....) anyway "she" got..hm..well i'll come right out..testies. I didn't know what there were so i thought she was dying. I took her to the vet to find out she was a he. LOL anyway, if you want to get a "friend" for you gerbil, i'd be carful i could never get mine to become friends, they'd fight. I even had that cage with a thing in the middle so t hey could spell each other but not come in contact. Its hard to get them to move in together, but you never know maybe mine had some prob..lol