Obviously reptiles such as alligators, crocodiles, Caymans, and the likes do not exist in Europe. They probably did have some knowledge of crocodiles, though, from the nile.
So, when the Spanish first started colonizing the Americas, did they learn about these creatures the hard way (getting eating by them), and ere their any other examples of them learning about dangerous creatures the hard way?
While there’s always more to say on the subject, you might enjoy this previous answer from u/sunagainstgold: