Artiodactyla

Artiodactyla ( ; ) is an order of placental mammals. Typically, they are ungulates which bear weight equally on two (an even number) of their five toes (the third and fourth, often in the form of a hoof). The other three toes are either present, absent, vestigial, or pointing posteriorly. By contrast, most perissodactyls bear weight on an odd number of the five toes. Another difference between the two orders is that many artiodactyls (except for Suina) digest plant cellulose in one or more stomach chambers rather than in their intestine (as perissodactyls do). Molecular biology, along with fos

Tylopoda (meaning "calloused foot") is a suborder of terrestrial herbivorous even-toed ungulates belonging to the order Artiodactyla. They are found in the wild in their native ranges of South America, Africa, and Asia, while Australian feral camels are introduced. The group has a long fossil history in North America and Eurasia. Tylopoda appeared during the Eocene around 50 million years ago.

mating season of ruminant mammals

A hoof split into two toes

Artiofabula is a clade made up of the Suina and the Cetruminantia. The clade was found in molecular phylogenetic analyses and contradicted traditional relationships based on morphological analyses.

Periptychidae is a family of Cretaceous–Paleocene placental mammals, known definitively only from North America. The family is part of a radiation of early herbivorous and omnivorous mammals formerly classified in the extinct order "Condylarthra", which may be related to some or all living ungulates (hoofed mammals). Periptychids are distinguished from other "condylarths" by their teeth, which have swollen premolars and unusual vertical enamel ridges. The family includes both large and small genera, with the larger forms having robust skeletons. Known skeletons of periptychids suggest generali

Arctocyonians (Arctocyonia; also known as "Procreodi") (from Ancient Greek ἄρκτος (árktos), meaning "bear", and κύων (kúon), meaning "dog", and thus, "bear-dog") are a clade of laurasiatherian mammals whose stratigraphic range runs from the Palaeocene to the Early Eocene epochs. They were among the earliest examples of major mammalian predators after the Cretaceous–Paleogene extinction event. While some classify arctocyonians as stem-artiodactyls, others have classified the group as members of Ferae. There are three families classified in the order: Arctocyonidae, Oxyclaenidae, and Quettacyoni

paired exocrine gland in many hoofed animals

thumb|A Jacob sheep with the polycerate condition Polycerates (meaning "many-horned") are animals with more than two horns.