Sida (Sido) is a great fertility hero whose travels link the Torres Strait to the Fly River peoples of the Papuan coast. In Islander tradition he journeyed through the strait as far as the Murray Islands, scattering and planting as he went and so introducing the food plants — and, in many versions, the sexual and reproductive knowledge — on which garden and human increase depend, before turning back westward toward Kiwai. His progress serves as a charter for the fertility of particular islands, and the wandering, generative pattern of his story places him among the peregrinatory culture-heroes whose cults Haddon identified as central to Islander religion. Sources vary in spelling his name Sida, Sido or Soido across the different island languages.