I have a 2 and a half year old flat coated retriever boy, who has started to develop black spots on his tongue slowly over the last six months or so. He has a larger one about the size of a pound coin far back, and two smaller ones about pea-sized near the tip, and they are completely flat on his tongue.
I know that black-spot birthmarks on the tongue are quite common in retrievers and are usually just extra pigment, and my dog's spots look identical to images of these birthmarks I have seen online. However my dog's spots have not been here since birth, can these birthmarks appear this late, or is this something I should get checked out by a vet?
He hasn't changed any behaviour with his tongue or general life at all, is showing no signs of pain in the slightest.
Many thanks for any help you can give me.