Mammal infraorders

Cetaceans are marine mammals belonging to the infraorder Cetacea (), a secondarily aquatic clade under the order Artiodactyla that include whales, dolphins, porpoises and extinct groups such as Basilosaurus. Most cetaceans live in marine environments, particularly the pelagic zone, but some reside solely in brackish or fresh water. Having a cosmopolitan distribution, they can be found in some rivers and all of Earth's oceans. Many species migrate seasonally over vast ranges for food advantages.

Lemuriformes is the sole extant infraorder of primate that falls under the suborder Strepsirrhini. It includes the lemurs of Madagascar, as well as the galagos and lorisids of Africa and Asia, although a popular alternative taxonomy places the lorisoids in their own infraorder, Lorisiformes.

The Hystricognathi are an infraorder of rodents, distinguished from other rodents by the bone structure of their skulls. The masseter medialis (a jaw muscle) passes partially through a hole below each eye socket (called the infraorbital foramen) and connects to the bone on the opposite side. This, together with their lack of an infraorbital plate and the relative size of the infraorbital foramen, distinguishes hystricognaths from other rodent groups. The infraorder's name comes from Ancient Greek ὕστριξ (hústrix), meaning "porcupine", and γνάθος (gnáthos), meaning "jaw".

Caviomorpha is the rodent parvorder that unites all New World hystricognaths. It is supported by both fossil and molecular evidence. The Caviomorpha was for a time considered to be a separate order outside the Rodentia, but is now accepted as a genuine part of the rodents. Caviomorphs include the extinct Heptaxodontidae (giant hutias), the extinct Josephoartigasia monesi (the largest rodent ever known) and extant families of chinchilla rats, hutias, guinea pigs and the capybara, chinchillas and viscachas, tuco-tucos, agoutis, pacas, pacaranas, spiny rats, New World porcupines, coypu and octodo

Adapiformes is a group of early primates. Adapiforms radiated throughout much of the northern continental mass (now Europe, Asia and North America), reaching as far south as northern Africa and tropical Asia. They existed from the Eocene to the Miocene epoch. Some adapiforms resembled living lemurs.

Viverroidea is a clade within Feliformia, containing both the family Viverridae, and the superfamily Herpestoidea.

Aeluroidea, Ailuroidea, or Feloidea is the name of a taxon (infraorder or superfamily) comprising cat-like Carnivora. More specifically the taxon comprises: either cat-like Carnivora in the broader sense, i.e. it is synonymous with Feliformia (more specifically either Feliformia sensu stricto, i.e. crown Feliformia, or Feliformia sensu lato, i.e. Pan-Feliformia); or cat-like Carnivora in the narrower sense, i.e. it comprises only the family Felidae (recently also Prionodontidae) and its closest extinct relatives. The Aeluroidea in the first, i.e. broader sense, has been sometimes called infr

Ctenodactylomorphi is an infraorder of the rodent suborder Hystricomorpha that includes two living families, the Ctenodactylidae (gundis) and the Diatomyidae (Laotian rock rat).

Ancodonta is an infraorder of artiodactyl ungulates including modern hippopotamus and all mammals closer to hippos than to cetaceans (whales). Ancodonts first appeared in the Middle Eocene, with some of the earliest representatives found in fossil deposits in Southeast Asia. Throughout their evolutionary history they have occupied different browsing and grazing niches in North America, Eurasia and Africa. The last continent is notable as they were among the first laurasiatherian mammals to have migrated to Africa from Europe, where they competed with the native afrothere herbivores for the sam