A pet saddleback tamarin hangs on to Yoina Mameria Nontsotega as the Matsigenka girl takes a dip in the Yomibato River, deep inside Peru’s Manú National Park.

As an evening storm lights up the sky near Wood River, Nebraska, about 413,000 sandhill cranes arrive to roost in the shallows of the Platte River.

Tempted by the fruit of a strangler fig, a Bornean orangutan climbs 100 feet into the canopy. With males weighing as much as 200 pounds, orangutans are the world’s largest tree-dwelling animals.

On a mountainside in Yosemite National Park, photographer Stephen Wilkes took 1,036 images over 26 hours to create this day-to-night composite.

Ye Ye, a 16-year-old giant panda, lounges in a wild enclosure at a conservation center in China’s Wolong Nature Reserve.

Silversides swirl through mangroves in the coral reefs off Cuba. The finger-size fish form large schools to try to confuse predators.

Lounging in inches of warm water, blacktip reef sharks wait for the tide to refill the lagoon at Seychelles’ Aldabra Atoll.

A baby African white-bellied tree pangolin hitches a ride on its mother at Pangolin Conservation, a nonprofit organization in St. Augustine, Florida.

The nervous system of this common octopus is larger and more complex than most invertebrates’. Can it think? Is it conscious? Researchers wonder if we’ll ever know.

Tortoises jockey for shelter from the sun. They will cook in their shells if they remain in the heat for too long.

Blood drips from a Rüppell’s vulture’s beak. The neck and head are sparsely feathered, which helps keep gore, guts, and fecal matter from clinging in a deep carcass dive.

In Alaska, a mother grizzly and her cubs cause a “bear jam” on Denali’s 92-mile-long Park Road, open to private vehicles only five days each summer.

Parts of the Yellowstone region are wilder now than they’ve been in a century. Grizzlies are spreading. This one, in Grand Teton National Park, fends off ravens from a bison carcass. Workers moved it away from the road to keep scavengers and tourists apart.

The colors of Grand Prismatic Spring in Yellowstone come from thermophiles: microbes that thrive in scalding water.

In Flint, Michigan, siblings Julie, Antonio, and India Abram collect their daily allowance of bottled water from Fire Station #3, their local water resource site.

To track changes in sea ice, the Norwegian research vessel Lance drifted along with it for five months in 2015, on a rare voyage from Arctic winter into spring.

The carcass of a bison that drowned in the Yellowstone River became a feast for this wolf and her two-year-old offspring.

Indigenous people farm and hunt in Peru's Manú forest but only for their own subsistence. Spider monkeys are a favorite quarry—and also favorite pets.

Twilight bathes the sanctuary of Athena Pronaia at Delphi. Pilgrims in ancient Greece may have offered sacrifices here before consulting the oracle of Delphi.

A diver keeps a close watch on a tiger shark in the Bahamas. But the scene may not be as dangerous as it looks: Tigers rely on surprise to hunt prey and are unlikely to attack divers who keep them in sight.

Dressed for Mars, space engineer Pablo de León tests a prototype space suit at NASA’s Kennedy Space Center, where fine soil and fans simulate conditions on the red planet.

Isra Ali Saalad moved from Somalia to Sweden with her mother and two siblings. “The reason we came to this country is because it is safe,” says her sister, Samsam.

A young Rüppell’s vulture eats a piece of zebra in the Serengeti. More dominant birds have taken their fill of the choice meat, leaving the skin and bones for other birds.

Photographs and paintings of sights such as this—the Grand Canyon of the Yellowstone— inspired Congress to create the park in 1872. It was a revolutionary step.

Gerd Gamanab, 67, sought treatment too late: Years of labor in the Namibian sun and dust destroyed his corneas. His blindness likely could have been prevented.

Poachers killed this black rhinoceros for its horn with high-caliber bullets in South Africa’s Hluhluwe-Imfolozi Park. Black rhinos number only about 5,000 today.

As the train nears the end of the journey at Kashgar station, a child draws a heart in the desert sand that came along for the ride.

Steven Donovan, flipping into a pool, took a seasonal job at Glacier National Park to sharpen his photography skills.

Virunga Park rangers in the Democratic Republic of the Congo undergo military-style training, including ambush tactics, due to the constant threat from armed groups.

Within sight of downtown Seoul, South Korea’s capital and a hub of modern stressful life, salesman Sungvin Hong rests after a hike in Bukhansan National Park.

On their first migration to their summer range in southeastern Yellowstone, three-week-old calves of the Cody elk herd follow their mothers up a 4,600-foot slope.

Villagers in Bagaran, Armenia, sing of cultural endurance and survival while picnicking at night beneath apricot trees—and a giant cross that shines defiantly into Turkey.

These rhinos on a South African ranch have recently had their horns trimmed. Unlike elephant ivory, rhino horn grows back when cut properly. The rancher is stockpiling the horn in hopes that selling it will soon be legal.

Igor Voronkin surfaces at the Barentsburg coal mine on Spitsbergen, in Norway’s Svalbard archipelago. Like most of the 400 other miners, he’s from eastern Ukraine.

The capital of Taiwan, Taipei comes to vibrant life when the sun goes down.

A panda keeper in China uses a stuffed leopard to train young pandas to fear their biggest wild foe. A cub’s reactions help determine if the bear is ready to survive on its own.

Eye-care workers use test-lens frames to conduct eye exams in India’s Sundarbans region. Their goal: to help reduce India’s blind population of more than eight million.

Becky Weed and her husband, David Tyler, raise sheep near Yellowstone National Park. They ranch with a guard dog to ward off coyotes, bears, and mountain lions.

At Fort Hall, Idaho, Leo Teton stands next to a pole ornamented with bison skulls, representing the spiritual connection between the Shoshone-Bannock tribe and bison.