campbells dwarf hamsters

Question
my hamster is bleeding on her bottom and I'm not sure why

Answer
Any time any animal is bleeding from its rectum, it needs to see a vet ASAP.  It could have prolapsed--meaning due to previous complications, your hamster has pushed out pat of its intestine.  In most cases, the animal will be euthanized as it is much more humane than letting the animal slowly bleed to death.  This likely occurred from either wet tail or another bacterial infection.  Sometimes small animals mask signs of illness until it becomes critical to get them vet attention as a survival mechanism.  In all likelihood, she will not recover on her own without treatment.

If she is being kept together with others, separate her immediately and montior the others for symptoms.  If she is kept with others, she could have sustained a bite injury which may be causing her to bleed but it's hard to say without other information.  Let me know if there's anything else I can do to help.

~Lauren