My daughter is in second grade and they did a unit on Charolett's Web. It is much heavier, so I think that RTT would be ok for first grade. You know your students. Some years you may have children who are not ready, other years they would be more than ready. This film is one of my favorites also.
Literacy: The book Slithery Jake written by Rose-Marie Provencher is a very cute story. They children could write in their journals what would their family do if they came home from school with a pet snake!
Art: As an extension of this story and movie we take a long piece of rolled colored paper. (Green, brown, yellow, white works best) The paper on rolls are typically thinner than regular construction paper allowing for better results. We then cut it to whatever length we wish. Typically 24" x 4". We do rubbings from automobile tire in the teacher parking lot. The rubbings give a very realistic look. The children draw eyes and can put a tongue on their snake if they wish. You could play around with this snake idea by making the head resemble a cobras head. If it is not possible to go into the parking lot for the rubbing activity, I have had a local mechanic bring in two or three tires into the classroom. He picks them up at the end of the week for me.
Social Studies: I would do a unit on snake/mongoose. It would be interesting to discuss that cobras are only found in certain parts of the world. Discuss local snakes that are found and maybe precautions if they were ever to encounter one while playing.
Math: You could have various paper snakes made yourselves in a variety of lengths. In the movie, one snake is tiny and others are large. Have the children measure them.
Science: Find a snake skin and look at it under the microscope. It is really facinating. I would fine a variety of book regarding snakes and mongooses for them to spend time enjoying them all week at the science area.
Hope this helps.
