Mackal is widely considered to be one of the seminal figures in the subculture of cryptozoology, a pseudoscience. According to writer Daniel Loxton and paleontologist Donald Prothero, "Cryptozoologists have often promoted 'Professor Roy Mackal, PhD.' as one of their leading figures and one of the few with a legitimate doctorate in biology. What is rarely mentioned, however, is that he had no training that would qualify him to undertake competent research on exotic animals. This raises the specter of 'credential mongering', by which an individual or organization faints a person's graduate degree as proof of expertise, even though his or her training is not specifically relevant to the field under consideration."