Tail hair?

[alligator]

One of my gerbils has longer hair near his butt/tail - he won't sit still to let me see if anything is wrong (like a tumor). But compared to his brother, he looks slightly different, but acts almost identical except possibly sleeping more.

Does this sound normal?

[thumpity]

Underneath his tail or on top? Maybe a pic would help...?? I have one gerbil whose scrotum sac hair looks like long hair sticking out from under his bottom near his tail when he is sitting or walking. Not sure if this was any help.
-Kaye