In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

A fossil with fermented grapes in its stomach of an early genus of these animals was found in the Messel Oil Shales. Darwin was astonished to discover a tooth from this extant animal group along with fossils of Toxodon, noting that Pliocene conditions must have been very different to cause their local extinction. George Gaylord Simpson drew them in a branching evolutionary tree, in contrast to their erroneous (*) anagenetic portrayal. Gould argued that passive diffusion could explain their trend toward increased body size; he also described their inaccurate textbook portrayal in "The Case of the Creeping Fox Terrier Clone," which deals with the genus Eohippus. For 10 points, name these perissodactyls, whose extant species are all members of the genus Equus.
Science