Why does jack wants other to fear a beast?

I have read the book recently and I don't think Jack and Ralph believe in the beast. They don't think its actually real, but the idea of the beast existing scares them. Jack even says(to cover his fear) that he and his hunters would find the beast and kill it in Ch.5. So, technically, they are scared but they don't show it as much as the littluns because they are older.