You may also be looking for the planet of the same name.

The Menk are a species native to the planet Valakis, living alongside the Valakians.

By 2151, they were primitive and relied on the Valakians for clothes, food, medical supplies and land to live on.

When the Enterprise visited Valakis to find a cure for the Valakian plague, Phlox researched the Menk's immunity to the disease. Phlox later discovered the the Menk were evolving and convinced captain Archer to leave the Valakians to attempt to discover a cure of their own. (ENT episode: "Dear Doctor")

By 2236, the Menk had become dominant, with their population reaching to the tens of millions while the Valakians had only a few hundred thousand people. They had discovered warp technology in 2236 and were admitted to the United Federation of Planets shortly there after. (ST reference: Star Charts)