[4] In the following centuries, independent tribal principalities arose in the valley incisions, still recognizable today by the location of the villages.

At first, only coastal regions with access to the important food source, the sea, were settled; with increasing population density, settlements grew in the valleys.

Little research has been done on the tribal society of Ua Pous; the German ethnologist Karl von den Steinen did pioneering work there in 1897/98.

It is considered that the real European explorer was the French circumnavigator Étienne Marchand (1755-1793), who arrived shortly after, on June 20, 1791, anchored with his ship Solide first in Vaiehu Bay, on the west coast, and then off Hakahau.

The arrival of the U.S. whaling ship Tuscan from Nantucket on March 4, 1835, was a prelude to other encounters with whalers, adventurers, and shady traders in the following years, who brought firearms and alcohol to the tribes.

The Matava'a festival is held periodically and is an important center of Marquesan culture.Geologically, Ua Pou is part of the Marquesas linear volcanic chain, which formed from a hot spot on the Pacific Plate and is moving WNW at a rate of 103–118 mm per year.

However, this may be related to the insufficient number of specimens collected so far; the steep and inaccessible peaks have prevented any systematic botanical study for the time being.

[11] The formation of the flora is strongly influenced by the trade winds, which contribute to lower temperatures and provide abundant rainfall.

In a bay separated from Hakahau by a peninsula (Anahoa Beach), green sea turtles (Chelonia mydas) lay their eggs.

In the main village of Hakahau there is a medical center, a national Gendarmerie station, the port authority, some small stores, a bank, a post office (with satellite telephone), some private pensions, restaurants, a Catholic and a Protestant church, a school with preschool (école maternelle et primaire) and a secondary school (collège).

In the north of the island, between the villages of Hakahau and Hakahetau, there is an 830 m long paved airstrip (IATA airport code: UAP) in a narrow valley.

The airfield is considered difficult because the runway starts right at the edge of the sea, ends in front of a mountain and has a considerable slope.

The main foods are still fish and other marine animals, as well as yams, taro, breadfruit, coconuts, bananas and other tropical and subtropical fruits.

The widely branched complex covers the entire valley, although the residential and ceremonial platforms hidden in the dense undergrowth are not easy to spot.

Karl von den Steinen believed he had identified the ceremonial platform (marae) where Chief Heato was buried.

He photographed the skeletal remains of his grandson Teiki Teiuao, which had been deposited on the stone pedestal in a celestial (temporary) burial.

[14] An excellent example of the island's highly developed stonework is an expressive tiki head made of light-colored Ke'etu tufa stone on the façade of a residential platform in the "Young Women's Plaza" (mata'aute'a).

The French Catholic mission in the Marquesas from 1838 to 1839 under the auspices of Admiral Abel Aubert Dupetit-Thouars did not initially have any consequences for Ua Pou.

Heato's daughter and successor, Teiki Teiuao, managed to unite all the tribes of the island under her hegemony in 1860 with the help of European firearms.