There are two heroes by this name in Greek mythology. Both were among the Argonauts, and each met his death at the tusks of a boar. They are often confused with one another.
Ancaeus of Arcadia
Ancaeus or Ankaios, son of King Lycurgus of Arcadia, was both an Argonaut and a participant in the Calydonian Boarhunt, in which he met his end. His arms were ominously hidden at home, but he set forth, dressed in a bearskin and armed only with a labrys or doubled-bladed axe. His wife was named Iotis, and his mother was either Cleophyle or Eurynome. Ancaeus' son Agapenor led the Arcadian forces during the Trojan War.
Ancaeus of Samos
This Ancaeus or Ankaios was king of the island of Samos, and an Argonaut: helmsmanship was his special skill (Argonautica 2.866ff). He was a son of Poseidon (Argonautica 1.186) and Astypalaea, and brother of Eurypylus. By other accounts his father was the Lelegian king Altes, which accords well with Ancaeus's rule over the Leleges of Samos. According to a lost epic of his house, sung by the Samian poet Asios, he married Samia, daughter of the river god Maeander, who bore him Perilaus, Enudus, Samus, Alitherses, and Parthenope, the mother of Lycomedes (Pausanias, Description of Greece, 7.4.1). The most famous story surrounding this Ancaeus is the following: When planting a vineyard - for Samos was famed for its wine - he was told by a seer that he would never taste its wine. Ancaeus then joined the voyage of the Argonauts, and returned home safely, by which time the grapes were ripe and had been made into wine. He summoned the seer before him, and raised a cup of his own wine to his lips, and was ready to taste it for the first time. He then mocked the seer, who retorted, "There is many a slip between cup and the lip". Before Ancaeus had tasted the wine, an alarm was raised that a wild boar was ravaging the vineyard, and on hearing this, Ancaeus dropped the cup and went out to investigate - and was promptly killed by the boar. (Pausanias, 1.30.4 and 5.15.6).
