Old maps are amazing. They show a much different version of the world than what we know. Prior to the further exploration into the interior of new countries there were writers like Pliny the Elder who wrote about the new creatures and people that he had heard about. One of the beasts Pliny wrote about was the Hydrus, this is not to be confused with the hydra.
The Hydrus was a snake type animal that lives in the Nile river in Egypt where it was considered a crocodile killer. The hydrus would allow the crocodile to roll it in the mud while it slipped into the crocs mouth. While in the crocs stomach the hydrus would eat it’s way through the side of the croc. Thus killing it.
The interesting fact about the hydrus is how it is described. Pliny states that it is type of river otter whereas Isidore of Seville lists the Hydrus as a type of snake. In Isidores description of the hydrus that caused those that it bit to swell up. But you would be able to cure the swelling with Ox dung. Isidore also noted that the smell of the beast is healthful. However; you wouldn’t want to put the hydrus in your food as the meat is poisonous.
I find the hydrus to be really interesting. In that there are two different descriptions of the hydrus that are widely different. Was it a otter or a snake? This was a new monster for me and I am interested in seeing if any of the other ancient writers wrote about the hydrus. I personally have only found the two descriptions of the hydrus. If you have seen another ancient author writing about the hydrus please let me know. I reviewed a few of the ancient maps that are online but I didn’t see the hydrus listed in Egypt.