Upon seeing an adorable Koala sitting on an eucalyptus branch in Australia, few would expect the beloved marsupial to emit a booming bellow to alert potential mates or rivals of its presence. But this powerful roar is just one of koalas’ many surprises, which delight and astonish in Australian biologist Danielle Clode’s new book, “Koala: A Life in the Trees.” Clode explores the enigmatic koala’s 24 million years-long saga of evolutionary adaptations, conservation triumphs, and endangerment catastrophes, and the prospects for their future following the 2019 bushfires that devastated Australia’s koala populations. We speak with Clode about the ancient ancestors, ecology, evolving relationship with humans, and uncertain fate of Australia’s bellowing marsupial.