Tangaroa is the great Polynesian god of the sea, known as Ta'aroa in Tahiti, Tagaloa in Samoa and Tonga, and Kanaloa in Hawaii, and he is the clearest single instance of a pattern that runs through Pacific religion: the same god holds sharply different rank from one island group to another. In western Polynesia (Samoa, Tonga) Tagaloa is the supreme creator, the sky-dwelling origin of the islands and the gods; in Tahiti Ta'aroa brings the whole world out of the confines of his own shell, a cosmogony of great beauty in which the shell becomes the sky and his body the land.
In Maori tradition and in Hawaii, by contrast, he is one great god among several, powerful over the ocean but not sovereign. This variation is not confusion but the natural result of related peoples developing a shared inheritance separately over centuries across a vast ocean. The fullest surviving version of the Tahitian shell cosmogony was set down by Teuira Henry, a Tahitian-American scholar working from manuscripts and oral testimony collected earlier by her missionary grandfather, published as Ancient Tahiti by Honolulu's Bishop Museum in 1928. In it Ta'aroa is described as dwelling, before creation, inside a cosmic shell called Rumia; splitting it open, he shapes one half into the sky and the other into the ocean depths and the land, a single act of self-division from which the whole visible world proceeds. Because this text rests on early nineteenth-century transmission through a single missionary-linked family line, scholars treat it as an invaluable but mediated record of Tahitian priestly tradition rather than an unmediated ancient scripture.