At any given instant, there are probably a small number of individual systems at the molecular level in your body that are in quantum superpositions, however for the most part, people (or cats) have undergone decoherence, and are thus best described as being in mixed states. To learn about the distinction between superpositions and mixed states, try reading this:
http://en.wikipedia.org/wiki/Mixed_state#Pure_and_mixed_states
The upshot is that superpositions are coherent, i.e. there is a well-defined phase relationship between the components of the state. Decoherence can be thought of as the process of degradation of the coherence. A superposition that undergoes complete decoherence ends up as a mixed state.