The further you go back in that history, the less likely those stories of exotic animals were less accurate. Here is a gorgeous collection of illustrations showing how people imagined real animals they had only heard about. Crocodiles from Liber Floridus (Book of Flowers), an encyclopedia by Lambert, Canon of Saint-Omer between 1090 and 1120.
Animals from the Rochester Bestiary, c. 1225-1250
A crocodile: Lions and other animals: A lion: A colorful panther: A crocodile from the Northumberland Bestiary, fol. 49v, mid-1250s
An elephant from the 13th century, by Guillaume le Clerc
An elephant from Italy, c. 1440
Lions from the Ashmole Bestiary (f.10v), 1511
A whale from Adriaen Coenen’s Visboek (Fish Book), 1560s
An elephant and a giraffe by Noè Bianco, 1568The History of Four-Booted Beasts and Serpents, by Edward Topsell, 1658 A beaver: A dromedary: A history of the Earth and animated nature, by Oliver Goldsmith, 1825 A hippo: Seals: Lions: A striped hyena, by Aloys Zötl, 1831Gibbons, by Aloys Zötl, 1833The Hoolock Gibbons, by Aloys Zötl, 1835 The Cheetah, by Aloys Zötl, 1837A rhinoceros, by Aloys Zötl, 1861A sea turtle, by Aloys Zötl, 1867A walrus, by Aloys Zötl, 1879________