HOW IS MONARCH BUTTERFLY MIGRATION POSSIBLE?

With a brain the size of a pinhead, the monarch butterfly uses the sun to navigate over long distances.

Monarch butterfly migration

The monarch butterfly is able to adjust for the movement of the sun and reach its destination.

Monarch butterfly on plant

With a brain the size of a pinhead, the monarch butterfly uses the sun to navigate over a distance of up to 4,830 kilometers (3,000 miles) from Canada to a particular forest and trees in Mexico—where their grandparents roosted the year before. The journey includes a stretch of 800 kilometers (500 miles) over open sea.

Some butterflies migrate over long distances.

Butterfly

Every March, clouds of monarch butterflies set off for Canada and their great-grandchildren return to Mexico the following October.

Monarch butterflies roosting

The monarch butterfly can adjust for the movement of the sun and reach its destination, a feat that has baffled researchers. The insect uses a circadian clock that is based on the 24-hour day to adjust for the earth's movement. Every March, clouds of monarch butterflies set off for Canada, and their great-grandchildren return to Mexico the following October.