An animal in a classroom is a great idea. It teaches students responsibility and gentlness. However, I have experienced snakes in a classroom and I was not a fan. My 4th grade teacher loved snakes and we had 4 aquariums with lizards and snakes. I dislike scaled animals and did not go near the slithering animals. I did love the hampsters that we had in our 5th grade classroom. They were sweet and fuzzy and liked to be held.
Whether the students like the animal or not, they are a good idea.