As a humanoid species they are on a developmental stage that is quite similar to humans. Their only distinguishing feature were their three bronchial tubes, and their encounters with Vulcans and Denobulans were always very cordial. However, a terrorist group of Suliban known as the Cabal wanted to increase their rate of evolution and so experimented in genetically engineering themselves, by acting as tools for a mysterious agent from the future, as a group involved in the Temporal Cold War. ENT episode: "Broken Bow"
Despite living as nomads, by the early 22nd century, many Suliban had settled and were living normal lives in the Tandar Sector. However, that all changed in 2144, when the Cabal began to launch attacks against the Tandarans. In response to the attacks, the Tandarans rounded up all the Suliban and imprisoned them. (ENT episode: "Detained")