Monarch Butterfly Biosphere Reserve

1986, the Mexican government created the Monarch Butterfly Biosphere Reserve to protect 62-square miles of forests within four separate monarch sanctuaries. The Biosphere Reserve was expanded to include 217 square miles in 2000.

Monarch butterflies are considered one of the world's oldest and most resilient species. Their life cycles depend on optimal conditions: temperatures between 55 and the low 70s when they migrate, an abundance of milkweed when they mate, and some rain during the winters.