The Ultimate Relay Race: The Monarch Butterfly Story - Preface

Monarch Butterflies are the original time travelers. They make the most remarkable journey of any living thing on Earth. It's a journey so mysterious, and wondrous, that a Monarch's migratory path is like a puzzle science is still unable to solve.

The mystery is complex. How do these brightly colored insects use their inherent skills to travel from Mexico, through the United States and even into Canada—what could be a 3000-mile (or 4,800-kilometer) trip—and then back to Mexico, covering between 50 to 100 miles a day? It's a year-long journey made all the more remarkable by this fact: It takes a Monarch four generations to make that round trip!

Four generations of Monarchs, making a single round trip, means that the first Monarch butterfly—the one leaving Mexico on the first leg—doesn't live long-enough to make the whole journey. In fact, it takes four generations to complete the migration and return home to where it all began. We could call this process a Monarch’s relay race.

How in the world does this happen? What special skills does a Monarch butterfly possess?

Monarchs are born with the ability to keep on the path that generations of Monarchs before them have traveled. They pass-on the ability to find their way back to Mexico before they die. This enables their descendants to complete the migration and return to winter in Mexico, or southern California, as their ancestors did.

Helping these butterflies to navigate this journey are two antennae in their bodies. One antenna helps them locate the sun while the other helps them assess the time of day. It's like they have a "genetically encoded compass" built into their bodies!