Camera traps can help illuminate the world’s most elusive animals. When a cougar, elephant or other creature triggers the device’s motion sensor, it snaps a picture.

“Most animals are hiding, you actually never get to see them and you might be led to believe there’s nothing out there,” said Roland Kays, a zoologist at North Carolina State University and author of the forthcoming book “Candid Creatures: How Camera Traps Reveal the Mysteries of Nature.”

Wildlife photographers have used remote-controlled cameras for more than a century, but in recent years scientists have begun using the tool with more frequency, Dr. Kays said. The images may be used to help researchers track the whereabouts of rare species or figure out what creatures inhabit a certain area.

The images below, from Dr. Kays and two other camera trap projects, offer some intimate glimpses into the secretive lives of wildlife, including lions roaming the wetlands of Namibia and coyotes dwelling in the forests of North Carolina.