rails trying to load prototype in production

I'm using jQuery and I have this line in my Application.rb:

    config.action_view.javascript_expansions[:defaults] = %w(jquery rails application)

Everything works fine in development, but in production I notice that Rails is trying to load all the prototype files and there's nothing in the production environment file that's telling it to do that. Why is it trying to load prototype?

If you look at the html (View > Page Source or similar in your browser) what do you see (presumably in the head) for loading javascript. Check it in development and then production mode.

Colin