  Bifurcations in a system of coupled maps are investigated. Using symbolic
dynamics it is proven that for coupled shift maps the well known
space--time--mixing attractor becomes unstable at a critical coupling strength
in favour of a synchronized state. For coupled non--hyperbolic maps analytical
and numerical evidence is given that arbitrary small coupling changes the
dynamical behaviour. The anomalous dependence of fluctuations on the system
size is attributed to these bifurcations.

Chaotic Dynamics;Chaotic Dynamics