 When Alan Williams was attempting to locate a monkey to use in the  film, he posed as a construction worker to gain access to a  University of Arizona biology lab to make face to face contact with  a scientist that worked with monkeys. The doctor was so impressed  with Alans tenacity that he referred him to local exotic animal vet  who then referred him to a private owner of Spider monkeys who  agreed to let him use a monkey in the shock scene.