In the Yukon, Porcupine caribou travel 3,000 miles. This is the longest migration by land of any mammal on Earth. Monarch butterflies fly about 3,000 miles each year. Some will travel all the way ...

The main basis for the proposal to list monarchs as threatened is that researchers are seeing fewer of the butterflies each year at their overwintering sites. There’s little debate that the monarch’s ...

Generations have watched in wonder as yellow-and-black striped caterpillars fold into green-and-gold chrysalises and emerge as large orange-and-black butterflies. Monarch's multigenerational migration ...

The monarch butterfly population continues to shrink due to factors such as climate change. People working to help the species say proposed federal protections could boost existing efforts.

Mexico's monarch migration arrived late this year but in greater numbers, say caretakers at the Monarch Butterfly Biosphere ...

Citizen scientists are called on to help with tagging monarch butterflies and find out why their numbers are dropping.