page_title: Creodonta
section_title: Extinction
hierarchical_section_title: Creodonta / Extinction
caption_attribution_description: Cynohyaenodon cayluxi skull-
context_page_description: Creodonta is an extinct, possibly polyphyletic order of carnivorous mammals that lived from the Paleocene to the Miocene epochs. Because they both possess carnassial teeth, creodonts and carnivorans were once thought to have shared a common ancestor, but given that different teeth are involved in making up the carnassials, this appears to be a case of evolutionary convergence. Carnassials are also known in other mammal clades, such as in the extinct bat Necromantis.
  Two distinct families were historically thought to compose the order: Oxyaenidae and Hyaenodontidae. They may both represent separate orders of fossil mammals related to carnivoramorphs or are descended from more basal taxa.
  Creodonts had an extensive range, both geographically and temporally. They are known from the late Paleocene through the late Oligocene in North America, the early Eocene through late Oligocene in Europe, from the early Eocene through late Miocene in Asia, and from the Paleocene to the late Miocene in Africa.
  Creodonts were the first large, obviously carnivorous mammals with the radiation of the oxyaenids in the late Paleocene.
context_section_description: It is not known exactly why the creodonts were replaced by Carnivora. It may be because of their smaller brains and their locomotion, which was somewhat less energy-efficient (especially while running). Their limb structure limited leg movement to a vertical plane, as in horses; they were unable to turn their wrists and forearms inward to trip, slash, or grab prey as modern carnivores can. Creodonts had to depend entirely on their jaws to capture prey, which may be why creodonts generally had a larger head size in relation to their bodies than carnivores of similar stature. The creodont lumbosacral spine was not arranged as efficiently for running as in Carnivora. The arrangement of the teeth was also somewhat different. In the miacids (as with the modern Carnivora), the last upper premolar and the first lower molar are the carnassials, allowing grinding teeth to be retained behind for feeding on non-meat foods (the Canidae are the closest modern analog to miacid dentition). In creodonts, the carnassials were further back—either the first upper and second lower molars, or the second upper and third lower molars. This committed them to eating meat almost exclusively. These limits may have created important disadvantages over millions of years.
caption: Skull of Hyaenodon
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