Every fall, monarch butterflies (Danaus plexippus) fly all the way to Mexico to spend the winter. As the temperatures warm in the spring, the monarchs travel north again.
I had heard this story many times, but I never really looked into the details. Monarch butterflies typically only live for a month. They eat, they mate, they lay eggs and that’s it. So how does this trip to Mexico over the winter fit into their life cycle?
Monarch butterflies that are starting their life in the fall have a different life cycle. These butterflies stop their development (this is called diapause), do not mate, and use that energy to live up to nine months and travel all the way to Mexico. Millions of monarchs congregate in one small area of Mexico for the winter, in Michoacan.
As the temperatures warm again in the spring, the monarchs resume their development, mate, and begin their journey northward. These butterflies don’t make it all the way back to where they were born, but their offspring will travel during their short lifetime, and then their offspring will travel some more. It takes several generations to complete the journey northward.
The news program 60 Minutes had a story about monarch butterflies and their amazing lives on April 20, 2025. You can read the transcript or watch the fascinating video on their website.
Have you seen a monarch butterfly yet this spring?