Monarch Butterfly: The Mass Migrating Butterflies of North America

What is a Monarch Butterfly?

A monarch butterfly is a butterfly in the family Nymphalidae. Monarch butterflies are primarily orange, with black stripes and white spots on the edges of its wings. They are commonly known for their migration made from Canada to Mexico, the longest migration route for any North American butterfly species.


Monarch caterpillars feed on only milkweed, which is a type of plant in the genus Asclepias. Adult monarchs feed on the nectar of a large variety of flowering plants, which include milkweed.


Small arthropods like ants and spiders like to feed on the larvae of monarch butterflies. Birds and wasps are dangers to adults.


Monarch butterflies are poisonous. They store a poison called Cardiac Glycosides in themselves, and get their poison from the poisonous milkweed plants they eat.

Life Cycle

Monarch butterflies lay eggs on milkweed plants. After seven days, the egg hatches into larva, or caterpillar. The larva sheds four times as it grows in size. After three weeks, the larva grows a chrysalis around  itself. With unique textures, patterns, and colors, the chrysalis blends in perfectly with the leaves to protect it from predators. After 15 days, the butterfly finally emerges from its chrysalis, transformed into a beautiful, winged insect.


Monarch butterflies born in late summer or early fall migrate up to 3,000 miles south, from the United States to Mexico and parts of southern California. Monarch butterflies migrate to find warmer weather in the south. They cannot survive the cold winters in most of the United States.

Monarch butterflies begin their journey in September or October, and arrive in Mexico during November. Strangely, monarchs often land in the same trees as their ancestors. Scientists are still stumped on how and why they do this. Then, monarchs hibernate through the Mexico winters, sleeping for around 4 months. They awaken in March, and begin mating. Shortly after the females lay eggs, the monarchs die.

The new generation of monarch journey back north for the abundance of food there. They arrive at around July, mate and produce eggs, then die. The whole cycle starts all over again.

Habitat Loss

Sadly, logging in Mexico reduces forests that monarchs used to migrate to. Efforts to prevent this from happening are being made, but illegal logging is still a threat to their habitat. Though monarchs are not endangered, they are listed as “threatened” by the International Union for Conservation of Nature.¬†This means that they are extremely close to being endangered.