An examination of genomic and other data from dozens of living and extinct penguin species is reported in Nature Communications this week, yielding insights into the bird's evolutionary history. Penguins originated more than 60 million years ago, evolving into highly specialized birds that developed wing-propelled diving and lost the capacity for aerial flight long before the formation of polar ice sheets. To date, phylogenetic studies have yielded insights into penguin evolution, yet have been limited by sampling issues. Genomic studies, meantime, have shed light on the diversification of extant penguins but have not integrated extinct species. In this week's study, a team led by scientists from the University of Copenhagen combined genomic data from all extant and recently extinct penguin lineages, stratigraphic data from fossil penguins, and morphological and biogeographic data from all species into a single framework, revealing key geological events that shaped penguin diversification and genomic signatures. Other findings include a suite of genes potentially underpinning adaptations related to thermoregulation, oxygenation, diving, vision, diet, immunity, and body size, which might have facilitated penguins' transition to an aquatic ecology. "These findings help improve our understanding of how penguins have transitioned to the marine environment, successfully colonizing some of the most extreme environments on Earth," the authors write