Internal Clock Leads Monarch Butterflies to Mexico

Publication: National Geographic News   Date: June 10, 2003   View Article

For every fourth or fifth generation of monarch butterflies that summer in the U.S. east of the Continental Divide, the pull of high-altitude Oyamel fir forests in central Mexico is irresistible.

By the millions each fall they point south and flutter up to 2,000 miles (3,200 kilometers) to reach the forests on a few small mountain peaks in an approximately 60-square-mile (155-square-kilometer) area in the volcanic highlands that serve as the butterflies’ winter retreat.

Related Posts

Seven signs of evolution in action

Glowing Butterflies Shine With Natural LEDs

Conservationists Name Nine New “Biodiversity Hotspots”

© 2008-2010 Collected Writings By John Roach