Francisco Pascasio Moreno (May 31, 1852–November 22, 1919) was a prominent explorer and academic in Argentina, where he is usually referred to as Perito Moreno (perito means "specialist, expert"). Perito Moreno has been credited as one of the most influential figures in the Argentine incorporation of large parts of Patagonia.
Moreno was born to Francisco and Juana Thwaites Madero in Buenos Aires. Raised in a traditional patrician family, he studied in local parochial schools. He shared his spare time with his father searching for artifacts and fossils, and at age 14, created a homemade museum of his extensive collections. Following graduation in 1872, he participated in the establishment of the Argentine Scientific Society, and embarked on the first of the series of expeditions that made him well known: a survey of Río Negro Territory, largely uncharted territory which had recently been made accessible by the controversial Conquest of the Desert campaign. In January 1876, he reached Lake Nahuel-Huapi, in the southern Andes, and discovered, on February 14, 1877, Lake San Martín. He also explored numerous rivers in Patagonia, and on March 2, he discovered and named Mount Fitz Roy since the native people also called other mountains Chalten.
In 1880, he embarked on a second expedition to the territory of Patagonia, where he was taken prisoner by a Tehuelche aboriginal tribe and condemned to death, but escaped on March 11, one day before the appointed execution. In 1882–1883 he explored the Andes from Bolivia southward, and in 1884–1885 he made new explorations of the territory south of the Río Negro and of Patagonia. He was the founder of the anthropological museum of Buenos Aires, chief of the Argentine exploring commission of the southern territories, and member of numerous European scientific societies.