Alicia
Adult Guinea Pig
I was just holding Roy and picking some wood shavings out of his fur and I felt a lump on his back. He's 5 years old. It's not hard, I poked it a bit (only to see if it was hard or not) and he didn't seem to mind me poking it. I haven't noticed this before but I don't hold him very often so I don't know how long its been there. What could this be?