Monarch butterflies look pretty, but taste horrible. Birds that eat these orange and black butterflies feel so sick they avoid monarchs for the rest of their lives. Those who have ingested a monarch usually avoid the viceroy too. The viceroy and monarch are hard to tell apart.The viceroy is slightly smaller and has an extra black band on its hind wing. For over one hundred years, scientists thought the viceroy was a non-toxic mimic that evolved over time to look like a monarch. This type of survival skill is called Batesian mimicry, after a 19th century naturalist named H.W. Bates. New research that came out in the 90’s suggests that this theory of monarchs and viceroys is a myth. In fact, the monarch and the viceroy are both foul tasting. By resembling each other, both species have a better chance of survival. This type of mimicry is called Müllerian mimicry. Many textbooks and websites continue to describe the viceroy as a Batesian mimic.