Paleontologist Mark P. Witton has contested this hypothesis, arguing that it ignores the existence of depictions of griffins throughout the Near East dating to long before the time when Mayor posits the Greeks became aware of "Protoceratops" fossils in Scythia. Witton further argues that the anatomies of griffins in Greek art are clearly based on those of living creatures, especially lions and eagles, and that there are no features of griffins in Greek art that can only be explained by the hypothesis that the griffins were based on fossils. He notes that Greek accounts of griffins describe them as living creatures, not ancient skeletons, and that some of the details of these accounts suggest griffins are purely imaginary, not inspired by fossils.