i just noticed today as my hamster was strangely awake on the secound floor this morning and when he stretched up it looked like he had blood on him but it was a red sore what could it be?
It looks like the fur on his shoulder fell out. Common causes are either he did some climbing and rubbed the fur off when he took a fall. Another cause was that he might be sick or affected with parasites. If he is acting extremely abnormal (eating habits, sleeping habits, poo color) hes probably is sick. Also, check under the chin. Normally, if ur hamster is affected by parasites, the underbelly fur is thin too. If you think its an injury, DO ALL THAT U CAN TO PREVENT INFECTION!!! Petstore often sell liquid bandage sprays. (dont spray into eyes) My hamster died of an infection ...
Your best bet would be to keep him comfortable, and take him to a vet.
Worst case scenerio it could be a tumor): or if you have other hamsters in there he could have gotten attacked and his injury has swollen. If he looks like he's in pain take him to the vet immidiatley to get it checked out.
