Absolutely no idea on his background, he's just a big boy and vet suggested maybe some Maine Coon. When we got him from the rescue shelter they told us he was probably 1-2 years old and wouldn't grow any more. Well, he more than doubled in size (more of him to love). There are two at the shelter where I volunteer that they are calling Maine Coon and my Swanie looks very similar to one of them.Unfortunately the only way to know, is if you know the background of the cat. Are one of the parents, or grandparents maine coon? It's part maine coon when one parent is maine coon, but then the other parent is not. 50/50 so to speak