What Are Some Facts About Monarch Butterflies?

monarch-butterflies Credit: Eric Bean/Photodisc/Getty Images

The monarch butterfly, or "Danaus plexippus," is a common butterfly with a large habitat due to its migration from North America to central Mexico. However, this migration pattern is considered a threatened phenomenon, and both the US and Mexican government are taking steps to make sure that these butterflies are protected during migration. Monarchs are also found in the Caribbean, Pacific Islands, Canary Islands and Western Europe.

The monarch butterfly begins its life cycle as a caterpillar, eating various plants of the milkweed family. Compounds in these plants make the monarch poisonous to predators. The larval stage in which the butterflies live as caterpillars lasts only two weeks. After this period, the caterpillar forms a chrysalis around itself and transforms into a butterfly after nine to 15 days. The adult monarch's distinctive orange color is a way to warn predators that the insect is poisonous.

Adult butterflies mate in the spring before migrating and lay their eggs once the migration is complete. Monarch courtship is unique because it is less dependant on chemical pheromones than the courtship of other butterflies of the genus. Males can be distinguished from females by the thickness of the black veins on their wings; females have thicker veins than males.

The monarch butterfly ranges throughout North America. It migrates 3,000 miles every year from Canada and northern parts of the United States to the Sierra Nevada Mountain range in California and Mexico for the winter. A group of monarch butterflies is called a flutter. Thousands of butterflies in a flutter often rest on a single tree during the long migration.

The monarch butterfly only lives between two to six weeks, maturing and producing the next generation before dying. Three generations are born, live and die during the summer without ever making the migration journey. The fourth generation, born in the late summer and early fall, makes the 3,000-mile round trip. This generation lives up to nine months, long enough to fly down and winter in California and Mexico and return to the ancestral breeding grounds before dying.