Elephants gathered at a watering hole in the relative safety of Serengeti National Park. In unprotected areas with dense human populations, the animals showed higher stress hormone levels.
After centuries of moving through the Irish countryside, a group known as Travellers has come to rest.
Algae, plants and humans: three groups of organisms that used chemistry to change the planet.
Peaks protected fifty years ago by the Wilderness Act no longer keep mountain goats safe from human impact.
By the 1920s, California had lost all of its grizzly bears—once considered a distinct species and an emblem of the state.