Shouldn't laugh, but this reminds me of my ex. I told him of the snakes that lived in the arctic. He said I was making it up, as snakes would be too cold. I simply laughed and told him that if he had ever seen an arctic snake on the telly, he would have known they were furry.
He did what he always does - did. He tells me he doesn't believe me, then I hear him telling his family about it.