In this excerpt from "The Story of the Mammals in 25 Discoveries," author Donald R. Prothero looks at a time when the idea of extinction was blasphemous.
Source: [Live Science](https://www.livescience.com/animals/extinct-species/giant-tusks-from-siberia-were-thought-to-be-the-horns-of-the-mythical-unicorn-what-medieval-people-made-of-fossils-before-vertebrate-paleontology)