 Several waves of human exploitation of the tortoises as a food source caused a decline in the total wild population from around 250,000 when first discovered in the 16th century to a low of 3,060 individuals in a 1974 census.Modern conservation efforts have subsequently brought tortoise numbers up to 19,317 (estimate for 1995–2009).The species "C. nigra" became extinct by human exploitation in the 19th century.