Deer from a chronobiological perspective

Chronobiology is the science of how organisms maintain synchrony with rhythmic variation in their natural environment. Over the past five decades, research in a select group of species has led to a consensus that daily synchrony is maintained via genetically encoded, innate circadian timer systems, which are a ubiquitous property of life. The current understanding of how year-round seasonal synchrony is achieved is, by contrast, less well developed and the role of innate circannual timers is a matter of continuing debate. Here, we consider how the behaviour and physiology of cervids is temporally organised, and the extent to which chronobiological principles usefully apply in this group. We also consider the contributions of deer biology to our understanding of chronobiology. Internal temporal programs emerge as the hidden masters of animal responses to changing energy demands throughout the year. Prospectively, understanding of these temporal programs is important or developments in farming and maintaining healthy biological synchrony in a changing world.