<p>Understanding the principles of animal behavior is essential for improving animal management and welfare in zoos. Here, the nocturnal patterns of ungulates are analyzed across multiple zoos. Interestingly, these patterns alternate between standing and lying down, and the present study aims to describe the degree of regularity and coordination of this behavior in a parsimonious stochastic model. The model assumes standing cycles (SCs), i.e., periods between standing-up times, to be regular and normally distributed. In addition, juvenile animals often showed less regular SCs. Therefore, it is assumed that the regularly occurring standing phases can be interrupted by short lying phases, resulting in lower regularity of observed SCs. For pairs of individuals, the standing-up times are assumed to be partly shared, and we measure the degree of this coordination using the cross-correlation function. In the dataset, juvenile animals exhibited increased interruption probabilities of standing phases, whereas the background regularity was not reduced. For pairs of individuals sharing the same box, coordination of the standing-lying activity ranged up to 100% and decreased with the distance between boxes. In addition, systematic delays between the standing activity of juvenile and adult animals are reported.</p>