Signalling may provide a means for the coordination and pacing of matings in mammals. To test this hypothesis in the wood mouse (Apodemus sylvaticus), two experiments were conducted. In the first experiment, which was designed to quantify, and explore the influences upon wood mouse oestrus, oestrus in the females caged singly, was relatively short (one day) and the oestrous cycle relatively long (up to 9 days). Further, in the presence of another two females in the same cage, the length of oestrus was slightly suppressed. However, prolongation of oestrus and curtailment of the oestrous cycle were typical for females caged with males from which they were separated by wire mesh. The main influence on the length of wood mice oestrus was the presence of alternating-unfamiliar males. The signals responsible for the modulation of oestrus and oestrus cycle are called passive signals. This is because they are unintentional and strongly dependent on internal physiological mechanisms, and also because the responses to them are of long duration (measured in days). The second experiment aimed to study the behavioural coordination of copulations. For this we used the Markov chain analysis for the long sequences of mating - which in this species emerges as a process which includes two distinct phases: precopulatory and copulatory behaviour, both of which have characteristic processes. These processes largely depend on the exchange of active signals, which are intentional and of a short duration. During the precopulatory phase, the male stimulates the female during grooming sessions and repeated anogenital contacts. During the copulatory phase, the male pursues the female - they repeatedly stop for intromission or ejaculation during mounts of very short duration. These phases are a female-driven process. Copulatory behaviour is, therefore, paced by the female's punctuation.