The Siege Onager is an improved form of the Onager in Age of Empires II. Like the Trebuchet, the Siege Onager can attack trees to eliminate them, thus plowing through forests. It is more effective at this task than the Trebuchet due to its large area of attack. It has more hitpoints, attack, and armor than the Onager, and like its lesser cousins may be used very effectively against infantry or archers. Aside from the different statistics and cosmetic look, Siege Onagers are the same as Onagers in design and function. Siege Onagers are only available to the Aztecs, Celts, Koreans, Mongols, Saracens, and Teutons.