The Viceroy Butterfly is a harmless butterfly that mimics the Monarch Butterfly. What is mimicry and why would an animal do it? Mimicry usually occurs when one animal is poisonous to the predator so another animal has evolved to look like it. Birds evolved over time to instinctively identify the pattern of the Monarch Butterfly as poisonous. (The Monarch Butterfly is poisonous due to its diet of poisonous milkweed). The Viceroy Butterfly has over time come to evolve to look much like the Monarch Butterfly so the birds leave the Viceroy Monarch alone.

Can you tell them apart? The Viceroy is on the right. If you look carefully, the Viceroy on the right has a black vein going across the bottom half of the wings, the Monarch on the left does not.