Very little is known of Mary Ryan, except that she was listed as "free" on the marriage documents when she married John Fiddler on Saturday, 20 January 1838. Mary is thought to have been born in Tipperary, Ireland in about 1812, the daughter of John Ryan.

Mary and John Fiddler had two children, Thomas, born in 1839 and Suzanna, born on Friday, 3 June 1842. Thomas died at the age of 10 or 11 in 1848.

Mary is known to have died as a result of the first ever railway accident in Tasmania on Saturday, 31 March 1877. She was recorded as being 64 years old at the time of her death, from which her birth year is presumed to be 1812. She was survived by her husband, John, her daughter, Suzanna.