In a recent article for the Smithsonian Magazine, Dr. Simon Groen noted that monarch butterflies, known for their striking appearance, are toxic due to the poisonous compounds in milkweed leaves they consume as caterpillars. They store these toxins in their bodies, using their black and orange color as a warning to predators. However, some predators have evolved to tolerate these toxins, creating an ongoing evolutionary arms race.

To learn more about these findings and explore how animals that ingest toxins use them for self-defense, visit the Smithsonian Magazine article, titled A Poisonous Diet Gives These Animals Their Own Toxic Defense.