The W and NW winds usually bring rain, but the rainfall is also heavy in the Southeast Monsoon period. At these times the weather is very variable, and days of rain are succeeded by bright and clear weather.
The E coasts are particularly unhealthful. Discolored water is often met with off the E coasts of Kepulaun Mentawai, although during surveys of this area no bottom was found with 183m of wire out.
The villages of Kepulaun Mentawai are small and rarely exceed 100 inhabitants. Siberut, situated on Pulau Siberut, at its SE end, is the only village of any importance. A Government official resides here. The inhabitants of the islands live mostly in the interior as the coastal areas are generally swampy.
In language, customs and appearance, the people are unlike those of Sumatera and their origin is uncertain. They are very primitive and wear little clothing. Both sexes are generously tatooed.
The people are peaceful and honest, but very shy.