The Mohawk Warrior has a nice combat bonus in jungles and forests, as well as another interesting advantage: it doesn't require Iron! The Iroquois are the only civilization whose Classical Era front-line unit doesn't require a resource, making it possible for them to immediately convert their Warriors into Mohawk Warriors without bothering to discover and secure Iron deposits. Then use them to attack enemies which are settled in forests or jungles, and defeat them easily, thanks to the special combat bonus!
The Iroquois Mohawk Warriors are among the best light infantry the world has ever seen. Amazingly fast and flexible fighters, the Iroquois warriors were able to cover an incredible amount of ground in a short amount of time, surprising and overwhelming their better-armed but slower European enemies. With an armed force that "never numbered more than 3,000 fighting men," they held their own for almost two centuries against the French, British, and Americans.