What can an armadillo tell us about blindness and an anteater about dental disorders? Many animals have evolved traits that are similar to human genetic diseases, although for these animals the traits are adaptive, not disease-causing. Intriguingly, when animals possess these disease-mimicking traits, they frequently have disabling mutations in the same genes underlying the human genetic disorders. Here we show how medical geneticists can leverage the genomes of these disease-mimicking animals, which range from blue whales to sloths and pangolins to naked mole-rats, to corroborate and discover novel gene-disease associations for diseases related to vision, teeth and other organs. (By Dr. Christopher A Emerling, http://jmg.bmj.com/content/early/2017/08/16/jmedgenet-2017-104837 )