; order Artiodactyla, suborder Ruminantia)
An infra-order that comprises the three superfamilies Traguloidea (chevrotains), Cervoidea (deer and giraffes), and Bovoidea (antelopes, cattle, goats, sheep, etc.). These form the most recent ungulate group, known since the Miocene, and are the most advanced of ruminants. The stomach is four-chambered, the upper incisors and in some forms the upper canines are absent, and the molars are selenodont. Only two digits are functional on each limb. Most members possess horns: these may be present only in the male, and used principally for intraspecific fighting; they are developed in some forms for ritualized contests that seldom cause injury. Tragulids, musk-deer (Moschidae), and some deer possess enlarged upper canines which are used in defence.
Subjects: Zoology and Animal Sciences.