In such forms the third and fourth metapodials fuse, partially or completely, to form a single bone called a cannon bone. In the hind limb of these species, the bones of the ankle are also reduced in number, and the astragalus becomes the main weight-bearing bone. These traits are probably adaptations for running fast and efficiently. Artiodactyls tend to share a number of cranial and dental characteristics, but the group is so diverse that there are exceptions to each trait. Horns or antlers are often present, usually on the frontals , which are usually larger than the parietals .
All artiodactyls have a postorbital bar or process.
The number of teeth is variable, but in many species it is smaller than the number found in perissodactyls. A diastema usually separates anterior and posterior teeth, especially in the lower jaw. Cheek teeth are bunodont in some forms, but more commonly selenodont . The premolars tend to be relatively small and not fully molariform. Most artiodactyls have modified stomachs , the extreme case being that of groups such as antelope and deer, which have distinctive, four-chambered stomachs.