Bjørn B Svingen, owner of a Polydactyl cat "I have heard people say that these genes came to Norway long ago. The story was that the genes were inherited from Spanish or Portuguese ship cats with this "'disorder'. These cats were supposedly common on ships trading on the Norwegian coastline. They have again become popular, at least in our area, and are plentiful in Trøndelag in mid Norway." As a result, they are also known there as "Skipskatt" (ship-cat).