Symbolism, Imagery, Allegory
An electric fence borders the Savage Reservation and separates the primitive world from the civilized world. The question, of course, is which is which? If you look at it in a certain light—a world of people subservient to their every desire and impulse, with no sense of restraint whatsoever vs. a world of ritualistic self-mutilation—neither looks particularly civilized (or particularly appealing). Also, did you notice that the electric fence is surrounded by dead animal carcasses? The pilot declares that these creatures "never learn," meaning seeing others die of electrocution doesn't condition the other animals out of leaping at the fence again. Conditioning is one of the dehumanizing processes in the World State, so it's interesting that animals in fact can not be conditioned.