Greek mythology features several dragons, but is there any evidence that these mythical monsters were based on real creatures?

Sounds like we might know what Will spit up in the sink, then. The original Hydra in mythology was actually the Hydra of Lerna, and in the Greek canon, killing it was one of Hercules' famed "12 ...

In Greek mythology, according to Britannica, the Hydra is a mythical creature with ... described as a divine warrior fighting the Sea, the Dragon (tannîn), and Leviathan (the Coiler).