Southern Monarch Danaus erippus

This South American beauty shares an astonishing secret: nearly identical genome to the North American monarch butterfly, yet the two are reproductively incompatible and classified as entirely separate species. Despite this genetic near-identity, they cannot interbreed. One of South America's best-known butterflies, it feeds on milkweed like its northern cousin. It's a perfect example of how DNA and evolution can drift apart while genetics stays frozen in time.