You’ve probably seen (in one version or another) the classic human evolution illustration—you know, the one in which monkey eventually stands upright to become man. It is less likely, though, that you have ever considered how we relate to fellow primates at the skeletal level. Well now, thanks to the eSkeletons website from the University of Texas at Austin, you have the chance to explore how humans, baboons, chimpanzees, and even ruffed lemurs (among other primates) are connected by cartilage. Showcasing 13 species in all, eSkeletons allows visitors to view individual bones by species, or compare a specific bone across all of the species represented on the site at once. Although there isn’t too much text on the site, there is a glossary that provides definitions for a number of anatomical and general biology terms.