Habitats for many extinct creatures are gone or conditions are perilous. Take the gastric-brooding frog. The species, known for converting its stomach into a uterus and vomiting tadpoles, was driven to extinction in 1983 by chytrid fungal infections. A project to clone the frog managed to get the cells of another frog species to replicate gastric-brooding frog DNA — a promising first step in restoring a gone-too-soon species. Not to mention the hostility other reanimated species might face if their interests run counter to those of humans sharing a habitat
