Ventral views of the skulls of a late Pleistocene, fossil Swift Fox, Vulpes velox, (left) compared to the same view of a modern Kit Fox (Vulpes macrotis). The greater size of the Kit Fox auditory bullae (the prominent rounded structures near the back end of the skull) despite the slightly smaller overall size of the skull is notable. The auditory bullae enclose the middle ear and often are larger in desert animals than in the same species or close relatives in damper climates.
Last Update: 11 Dec 2006