Figure 1.

Dorsal views of the cerebral hemispheres of four carnivore species. The yellow box indicates the approximate area of the frontal cortex, defined as the cortex rostral to the cruciate sulcus (cs). Note the relative volume differences among the species. The relative amount of frontal cortex appears greatest in dog and spotted hyena. Other abbreviations: PR, proreal gyrus; prs, presylvian sulcus; psd, post-cruciate dimple. Whole brain images from the University of Wisconsin Comparative Mammalian Brain Collections (supported by the National Science Foundation) at http://www.brainmuseum.org.