Thanks to modern science, there are more ways than ever before for humans to save wild animals from extinction. But in her new book, M.R. O’Connor argues that most of these methods–like zoos re-creating complex natural environments–are masking a larger issue: the need to save natural habitats. Tigers, for instance, have lost 93% of their territory in the past 100 years, mostly to deforestation. Caribou have lost half. And dozens more species, including the Hawaiian crow, have lost their entire habitats; now they exist solely in captivity. Recently the science of conservation expanded to include resurrection. In 2009, a group of Spanish researchers successfully gave life to a Pyrenean ibex, which went extinct in 2000. (The resurrected ibex, though, lived only a few minutes.) And there are efforts elsewhere to resurrect the woolly mammoth. But O’Connor remains bearish. “Until we make space for other species on Earth,” she writes, “there won’t be many places left for them to exist.”
This appears in the October 05, 2015 issue of TIME.