All fox, mink and marten that have been lawfully imported or acquired, or bred or reared in captivity or enclosures, are declared to be personal property. Any person hereafter acquiring any such fur bearing animals in the wild state, shall within ten days furnish satisfactory proof to the director that such animals were lawfully obtained. Such wild animals shall not become personal property under the provisions of this section until such proof is furnished.
RCW 16.72.030