Big Hamster butt

Question
I have a Dwarf Hamster, and I'm just wondering if there is a reason that the butt is odd shaped and somewhat protruding.  It seems to be larger some days than it is others.  Is it related to diet/health/nutrients etc.?

Thanks!

Answer
Dear Tim,
thank you for your questions.
It's sex-related ;) You have a male hamster and what you describe as odd-shaped are the hamster's testicles. They can grow huge, especially with Syrian and Chinese dwarf hamsters. The testicles tend to get bigger when it's warm.
I hope I was of some help
Jennifer