lonely gerbil

Question
a month ago our one gerbil died and left our other friendless. at first, that same day he seemed very shakey and sleepy but we kept handling him and playing with him and giving him treats and for a while he was better. but today, a month later, he seems agressive. he is in a 10gallon fish tank with a wheel and water bottle and toilet paper tubes and even a tissue box. but he keeps getting on top of the tissue box and jumping up and hanging upside down from the tanks screened lid. when we go to lift the lid he does this and i'm pretty sure he is trying to bite us. is this normal? is it b/c he is lonely? like i said, we play with him numerous times a day and make sure he is fed and tank is clean. we are not sure what to do.

Answer
Dear Shannon,
thank you for your question.
I think it's very possible that the gerbil is bored and lonely. Even if you play with him a lot, he is spending the majority of his time alone and gerbils are very social.
Gerbil introductions can be very long-winded and complicated, but don't loose patience. A young gerbil between 6-8 weeks works best, but it's also possible to introduce two older gerbils. Here's some good info on how to introduce gerbils:
http://www.das-maeuseasyl.de/doku.php/en/species/mongolian_jird#introducing_gerb...
http://www.egerbil.com/splittank.html

I would also recommend getting/building a bigger cage once the two gerbils are living together peacefully, they really will love and use the extra space.
http://www.egerbil.com/care.html#care-middle-tab-3

I hope I was of some help to you
Jennifer