A mother honeyguide has placed its chick into a bee-eater’s nest— puncturing all the other eggs in the nest and leaving only its own hatching alive. Over the following weeks, the host parents devotedly care for the hatchling whose mother murdered their offspring. This is brood parasitism, a phenomenon which is especially well-known among birds. Steve Rothstein digs into the evolutionary strategy. Lesson by Steve Rothstein, directed by Mauricio Bueno, Lucy Animation Studio.