The playful North American river otter is equally at home in the water and on land. It makes its home in a burrow near the water's edge, and can thrive in river, lake, swamp, or estuary ecosystems.

A map showing seismic speed in Earth’s crust at 125 miles depth across the continental U.S. and portions of Central America and Canada. The North American craton (outlined in black dashes) has a ...

North American species like the Colorado potato beetle and the fall armyworm have become invasive elsewhere. Illustration by Marilyn Foehrenbach Q: In North America, we worry about invasive ...

The largest of all North American frogs, this giant can grow to a length of 8 inches or more and weigh up to 1.5 pounds. Even the tadpoles of this species can reach 6.75 inches in length.

Whether born slave or free, African Americans in the North found themselves at the center ... Maria Stewart was America's first female African American political writer. Producing most of her ...