A unifying, eco‐physiological framework for animal dormancy

Abstract Various animals across the tree of life express some form of programmed dormancy (e.g. hibernation, diapause) to maximize fitness in highly seasonal environments. The integrated phenotype of animals undergoing programmed dormancy is strikingly similar among diverse groups; however, research on programmed dormancy has historically been phylogenetically siloed. A broad comparative approach could clarify new angles for answering fundamental questions about programmed dormancy evolution. To advance this approach, we present a cross‐taxonomic framework describing dimensions that distinguish animal dormancies and provide a set of core traits that animals regulate as they progress through the eco‐physiological phases of deep, programmed dormancy. We use this universal framework to explore the ultimate drivers and evolutionary consequences of dormancy across the tree of life. Deep, programmed dormancy appears to be a predictable and repeated adaptation to highly seasonal environments that draws on a conserved suite of ancestral traits. We highlight evidence for molecular convergence in signalling pathways coordinating environmental sensing and energy metabolism in the insect and mammal lineages, separated by 700 million years of evolution and representing independent colonizations of highly seasonal environments. Lastly, we discuss the utility of this new framework and highlight opportunities and challenges for researchers to continue advancing our understanding of dormancy through a broad, comparative lens. A free Plain Language Summary can be found within the Supporting Information of this article.