  We explore the quantum-classical crossover of two coupled, identical,
superconducting quantum interference device (SQUID) rings. We note that the
motivation for this work is based on a study of a similar system comprising two
coupled Duffing oscillators. In that work we showed that the entanglement
characteristics of chaotic and periodic (entrained) solutions differed
significantly and that in the classical limit entanglement was preserved only
in the chaotic-like solutions. However, Duffing oscillators are a highly
idealised toy model. Motivated by a wish to explore more experimentally
realisable systems we now extend our work to an analysis of two coupled SQUID
rings. We observe some differences in behaviour between the system that is
based on SQUID rings rather than on Duffing oscillators. However, we show that
the two systems share a common feature. That is, even when the SQUID ring's
trajectories appear to follow (semi) classical orbits entanglement persists.
