The more ancient of the two placental mammalian carnivorous orders, an extinct order comprising two families (Oxyaenidae and Hyaenodontidae), which appeared in the late Cretaceous and dwindled to extinction in the Pliocene. Oxyaenids (e.g. Oxyaena) were rather weasel-like, although some of them were large (Patriofelis was the size of a bear). Hyaenodonts had narrower skulls, longer legs, and well-developed carnassials, and diversified into forms reminiscent of the dogs, cats, and hyenas. Only the hyaenodonts survived the Eocene, and filled the role of scavengers until they were displaced by the modern hyena. Creodonts were small-brained and slow-moving, and are not closely related to modern carnivores.