Introduction
Deucalion is a son of the Titan Prometheus, and the central human survivor of the Greek flood myth, functioning in Greek tradition much as Noah does in the biblical account or Manu in Indian tradition: the one man, forewarned, who preserves humanity through a divine deluge.
Family
Warning and the ark
Zeus, angered by the wickedness of the Bronze Age of humanity (or, in some versions, by King Lycaon's specific impiety in serving him human flesh), decided to destroy humankind with a great flood. Prometheus, ever humanity's ally, warned his son Deucalion in advance and told him to build a chest or ark.
Survival and new humanity
Deucalion and his wife Pyrrha survived nine days and nights adrift on the floodwaters before landing on Mount Parnassus. Following an oracle's cryptic instruction to throw "the bones of their mother" behind them, they cast stones, which became a new race of humans, Deucalion's men and Pyrrha's women.
Ancestor of the Greeks
Deucalion and Pyrrha's son Hellen became the legendary eponymous ancestor of the Hellenes, the Greek people's own name for themselves, making Deucalion, in effect, the mythic second father of the entire Greek nation after the flood.