There was also the problem of an ever-expanding number of known species: for Kircher and earlier natural historians, there was little problem finding room for all known animal species in the Ark, but by the time John Ray (1627–1705) was working, just several decades after Kircher, many more had been found. Incorporating the full range of animal diversity into the Ark story was becoming increasingly difficult, and by 1700 few natural historians could see any reasons to believe in a literal interpretation of the Noah's Ark narrative.