Monarch Butterfly


  • Scientific Name
    Danaus plexippus
  • Weight
    less than half a gram
  • Length
    Wingspan 4 IN.
  • Habitats
    Forests, Mountains

Monarch butterflies embark on a marvelous migratory phenomenon. They travel between 1,200 and 2,800 miles or more from the United States and Canada to central Mexican forests. There the butterflies hibernate in the mountain forests, where a less extreme climate provides them a better chance to survive. The monarch butterfly is known by scientists as Danaus plexippus, which in Greek literally means "sleepy transformation." The name evokes the species' ability to hibernate and metamorphize. Adult monarch butterflies possess two pairs of brilliant orange-red wings, featuring black veins and white spots along the edges. Males, who possess distinguishing black dots along the veins of their wings, are slightly bigger than females. Each adult butterfly lives only about four to five weeks.

The great monarch migration

Every year, the Eastern monarch butterfly flies up to 2,500 miles from its breeding grounds in the US and Canada, all the way down to its hibernation grounds in central Mexico. These tiny creatures have the most highly evolved migratory pattern of any known species of their kind, but this unique phenomenon is under threat.

Monarch butterflies

Why They Matter

  • The monarch butterfly exhibits the most highly evolved migration pattern of any known species of butterfly or moth and perhaps any known insect.


Swarm of Monarch butterflies

Habitat Loss

Monarchs need mountain forests in Mexico for their winter habitat, however nearby human communities also rely on them and create pressure on forests through agriculture and tourism activities.

In the U.S., monarchs need places to reproduce and feed. However, herbicide use is decreasing the availability of their primary food source, the milkweed plant (Asclepias).  

Climate Change

Climate change threatens to disrupt the monarch butterfly’s annual migration pattern by affecting weather conditions in both wintering grounds and summer breeding grounds. Colder, wetter winters could be lethal to these creatures and hotter, drier summers could shift suitable habitats north. WWF’s 2013 report from Mexico showed that the number of monarch butterflies wintering there was at its lowest in 20 years. The number is measured by the amount of forest they occupy, and in 2013 the number of butterfly acres decreased from approximately seven to three. Abnormal patterns of drought and rainfall in the U.S. and Canada breeding sites may have caused adult butterfly deaths and less plant food for caterpillars. Fewer butterflies up north mean fewer then migrate south to Mexico for the winter.

What WWF Is Doing

Monarch Butterfly

WWF works to preserve vital butterfly habitat in Mexico’s Monarch Butterfly Reserve by working with the Mexican government, local communities, and other partners to promote good forest management and sustainable tourism. WWF also supports tree nurseries that help restore the forest in the Reserve which creates new sources of income for the local communities that live in the region. 

In the United States, we're also taking a variety of measures to help save the monarch butterfly migration. By working with many leading US food companies and other environmental organizations to help farmers increase the biodiversity on their lands and reduce the impact that crop production has on our environment, we are taking steps to preserve monarch habitat.  

Read more about WWF’s work with local communities to protect monarch habitat in Mexico.

Related Species