We see a fish tank used as a glass cage for closely packed rats on an
animal market in Mexico City. We see how rats, known for their distinct
social intelligence, behave when confined to a much too small
environment. They ruthlessly climb on top of each other in a continuous
and futile striving for the top. Each against all. This scene can be
interpreted as the struggle for survival in microcosm, in a social
system with hardly any perspective.
The notice on the glass
"Exportacion" (Export) could be read as an omen.