Extant ungulates can be divided into three dietary categories: browsers, grazers, and mixed feeders. Dietary adaptations can be differentiated in extant ruminants based upon analysis of premaxillary shape. This study applies methods to determine the dietary adaptations of extinct ungulates through analysis of premaxillary shapes. While browsers have pointed premaxillae and grazers have square premaxillae, mixed feeders have premaxillae that are a shape intermediate to the browsers and grazers, sometimes accompanied by an indentation on either side of the incisive foramen, which results in a club-shaped premaxilla. Cranioceras skinneri (Palaeomerycidae), Dromomeryx whitfordi (Palaeomerycidae), Palaeotragus coelophrys, “Palaeotragus” primaevus, an undetermined species from the Baringo Basin of Kenya (Giraffidae), Texoceros guimonensis (Antilocapridae), and Turcocerus grangeri (Bovidae) were found browsers; Aletomeryx gracilis (Palaeomerycidae), Bramatherium megacephalum (Giraffidae), Cosoryx furcatus (Antilocapridae), Honanotherium schlossen (Giraffidae), Samotherium boissieri (Giraffidae), Samotherium neumayri (Giraffidae), Samotherium sp. nov., Sivatherium giganteum (Giraffidae), and Synthetoceras tricornatus (Protoceratidae) were grazers; and Merycodus necatus (Antilocapridae) and Palaeotragus rouenii (Giraffidae) were mixed feeders.