The old Ancestry 'rules' said that anyone without a death date entered who was less than 100 years old was considered as 'Living'. On Ancestry, anyone classed as 'living' would not have any of their details shown on public trees. Many people's trees have ancestors who are known to be dead, but do not have a death date, because one cannot be found. The new Ancestry system allows people to show ancestors as 'dead', even though an exact death date is not known, which then makes their details viewable on public trees. If you are not sure that someone is dead, you should click the button that shows them as being alive.