Hamster Fact: They are one of the few rodents that don't have a long naked tail. They have a short naked tail instead! :) One of the diseases that can affect a hamster is wet tail. This is a bacterial disease that affects the digestive system of the hamster and can cause diarrhea and dehydration in the animal. It can be caused by stress or if the animal is young and weening. It could also be caused by poor living conditions so it is important to clean out their cages once a week with soap and water. If they get wet tail it is best to take your hamster to the vet. Sometimes over the counter treatments are not enough for your pet and the vet can help with hydrating your animal as well. More info here.