The Ventu were an indigenous society of Ledosians native to the planet Ledos in the Delta Quadrant. They are related to the Ledosians, who believe them to be representative of their evolutionary precursors. The Ventu have no spoken or written language and communicate through signs.
Unlike the Ledosians, the Ventu did not become technologically advanced. Early in their shared history, the Ledosians came into conflict with the Ventu and polluted their homeland. As a result, Species 312 erected an energy barrier over the Ventu's territory on the southern continent for their protection. The Ledosians eventually developed into a warp-capable civilization, while the Ventu remained a tribal hunter-gatherer society.
In 2378, a USS Voyager shuttlecraft carrying Commander Chakotay and Seven of Nine accidentally crashed into the barrier. The two were marooned inside, but were able to neutralize the barrier with the help of the Ventu. However, the Voyager crew restored the barrier when it was said that the Ledosians planned on observing the Ventu, thus interfering with the Ventu way of life. (VOY: "Natural Law")