Determination of Smilodon fatalis (Carnivora: Felidae) brain volume and its place among extant felids by use of MicroCT scans

After Leidy discovered Smilodon fatalis in 1869, Merriam and Stock became interested in this felid. They made the first endocast. Since then, the external cranium of the sabertooth cat Smilodon fatalis from Rancho La Brea has been extensively studied; however, few endocasts have been made for this iconic animal. We demonstrate the flexibility of 3D Slicer to produce endocasts while showing that accurate endocast volumes can be created for specimens that have tar-based matrix in the endocranial region. To verify our accuracy, we recreate an endocast previously produced in latex and measured. We use MicroCT scans to create five new endocasts and we relate these casts to the basal lengths of the skulls we created them from. Additionally, we compare these new results to extant felids finding that the range of brain endocast volumes are similar to modern lions.