The Monarch Butterfly

The natural phenomena of the Monarch Butterfly migration was recently discovered. During the 1960s a group of Canadian and American scientists began wondering what happened to the butterflies they saw in their gardens during the summer as they disappeared during the winter. The scientists decided to mark and follow the butterflies and after several years of hard research in the late 1970s they finally ended in the central mountains of Mexico where these beautiful insects come to hibernate.

Every year the Monarch Butterflies return to the same high mountains located in the states of Mexico and Michoacan. These mountains are part of the Transverse Neovolcanic Chain that runs from the Eastern Sierra Madre until it joins the Western Sierra Madre. As its name says, many volcanoes are located in this area, and several of them are still alive. From the 9,000 and up to the 12,000 feet over sea level these mountains are covered with dense fir tree forests. The Monarch Butterflies come to these fir tree forests looking for shelter against the wind, the rain and the cold. At the same time, this forest provides the butterflies with food and humidity to keep them alive during their hibernation period.

Coming from the Eastern side of Canada and the USA, the Monarchs fly more than 4,000 kilometers to arrive to Mexico during the last days of October or the first days of November. On November the 2 nd , the Mexican people celebrate the traditional festivity of the Day of the Dead and an old legend tells that these butterflies are the souls of dead people coming back to visit their beloved ones. From 60 to 90 millions Monarchs arrive each year to the same five or six sites; and the high density of them transforms the evergreen fir trees into beautiful orange/brown trees.

After four months in hibernation, these marvelous insects become active again and get ready to fly back to the north. The butterflies mate in the fir tree forest and with their last energy reserves depart from Mexico around March 21 st . They will barely make half of the journey back to the place from where they came. Most of them will lay their eggs on the milkweed plant found in the Southern states of the USA and then die.

With the beginning of spring, millions of eggs hatch on the milkweeds. The caterpillars eat the leaves of this plant and take advantage of its poison in order to become poisonous butterflies for the birds that would like to kill them. This new generation of Monarchs will continue flying to the north until they reach the place from where their parents began flying several months before. After a short life of only 2 to 6 weeks this generation will mate, lay their eggs and die. This process continues during spring and summer when Monarchs with a short life span brighten up thousands of gardens in Eastern Canada and USA.

The Monarch Butterflies born during September have a different and special destiny. They will have to fly south looking for warmer latitudes in Mexico in order to escape from the cold winter. This special generation will have a very long life span of about six months. They will make the amazing journey to the Mexican mountainous fir tree forest. They will arrive exactly to the same trees from where their ancestors departed several generations ago.

Up to now humans have not been able to understand how Monarch Butterflies can find their way through 4,000 kilometers while crossing different types of country with a great diversity of weathers. This is an incredible miracle that shows how little science knows about Mother Nature!