Kroots

The Kroot (Krootis aviana), also designated by the Imperium as Kroot Carnivore, are a xenos species of savage humanoids who are members of the T’au Empire. The Kroot evolved from avian creatures on their homeworld of Pech. Kroot are tall (a good half-metre taller than most Humans), their avian ancestry giving them a bird-like beak and long quills protruding from their heads like hair. Smaller quills, possibly the evolutionary remnants of feathers, can be found scattered over their bodies. A unique feature of the Kroot is that they evolve by selecting genetic traits of their defeated foes to absorb by eating them. Due to this, the many Kroot warbands across the galaxy often look radically different. Kroot leaders are known as Shapers; they are generally the Kroot with the best ability for recognizing desirable traits in defeated foes and tell their kindred.