Shalom aleichem,

I was hoping that you could help me out with some questions.

On daf 33a in the gemara Berachos the arod is mentioned in the context of something that happened with Rebbe Chanina ben Dosa;

An arod was bothering the townsfolk and R. Chanina took care of the situation; he stuck his ankle into the hole where the Arud lived, and when the arod bit him, the Arud died;

R. Chanina brought the arod to the Bais Midrash so all could see that it is only sin which kills; R. Chanina is free of sin and Oy to the arod that bites R. Chanina.

Rashi explains that the arod is a crossbread of a snake and a toad.

Rashi also explains this incident according to the "Halachos Gedolos", that if a person is bitten by an arod and the person reaches water before the arod, then the arod will die; but if the arod reaches water first, the person will die. (A miracle occured and a spring opened up beneath R. Chanina's heel.)

(a) An obvious question is: how could R. Chanina place himself in danger and, furthermore, how could he rely on a miracle?

But that is not my quesion.

(b) My question is: has there ever been such a thing as an arod??? and how could a "race to the water" determine the effectiveness of venom?

From the perspective of modern zoology, snakes and toads cannot crossbreed, and the venom of a snake is not affected by whether the snake or person reaches the water first.

Lets assume that Rashi would agree with modern zoology. If so, then why does he explain the pshat of the Gemara this way?

Or, if we assume that Rashi would not agree with modern zoology, how should we understand this? Has nature changes since the time of Rashi? or at least from the time of R. Chanina(which Rashi is coming to describe)?

Thank you for you time and consideration.

David Avraham Landau