The cause of their extinction was the arrival of the Maori. As soon as the Maori landed in NZ, their ferocious appetite for native speicies wiped out firstly, the moas (peaceful 3 metre tall native flightless birds).
Then the kiwis (another native flightless bird) neared extinction until the dormant cannibalism of the Maori kicked in.
The Maori realsied that Moriori were a far better game than the small meatless kiwi, so the Maori hunted down the Moriori, fed upon thir internal and sexual organs to grow bigger, stronger and blacker.
The poor Moriori were forced to flee their homeland to a remote island of Chattam.
This day, the Moriori cease to exist, but only in myths they are spoken of.
The Maori maoried the Moriori man's penis and cooked it in the hangi
Fish n Chips are now the repacement of Moriori for the Maori
The Moriori pre-Maori myth was constructed by Elsdon Best and Stephenson Percy Smith. Through a selection of Maori tales and history, partnered with their own theories of Maori origin. This belief became popularized in the early 20th century and persisted in the education system until at least the 1970s. But continues to stay in the public mind. Which placed an advantage- from a European settler view- justifying the disenfranchisement of Maori.
'Notably, the concept also undermines notions of the Māori as the indigenous people of New Zealand, by portraying them as conquerors.'
Historians, Anthropologists and Ethnologists have debunked the theory since the 1920's. Academics agree that the Moriori share the same Polynesian ancestry as Maori people. Also sharing similarities in their language and customs. Indicating that Moriori came to the Chatham Islands from New Zealand about 1500. Through their isolation developed a strong pacifist society; the Nukunuku law.
A tall, peaceful, and very dark-skinned race of people, they are often listed as Polynesian, but in fact originated in South America.
They were superb gardeners who grew the kumara, or sweet potato, which was a native of their South American homeland, and taught its cultivation to the later arriving Maori.
What remains of their geneology survives today on the Chatham Islands, to where they were driven from the New Zealand mainland islands, and to where Maori pursued and attempted to annihilate them.