This one was a hunting mastiff from the north of Italy. My guess is the scars come from the dog’s use as a boar catcher. I doubt that the dog is 10 or 12 years old, but it is certainly an older dog. This is probably very similar to the kind of mastiff-type that the Alani would have had.
You mean it wasn’t a Neapolitan Mastiff ;-)
I think it looks like the left ear was actually bitten off? Looks a little like that from the video. Although I am well acquainted with the Frick (my Holbein ancestor has a couple of portraits hanging there) I don’t remember this painting which I find odd… The painting is well crafted and clearly was well cleaned since it doesn’t show any darkening as with many paintings of this age. I don’t know how I let this one get by me…