Nat Geo photographers recall their favorite shots on Endangered Species Day

A silverback gorilla rising out of the underbrush on a cloudy day. A tigress nursing her newborn cub at the mouth of a cave. An orangutan climbing a hundred feet into the forest canopy.

Most of us will never witness such rare moments, but we can experience them all the same, thanks to the perseverance of wildlife photographers. Some of these shots are the products of decades of experimentation, fine-tuning, and long hours spent in remote places getting eaten alive by flies, mosquitoes, and leeches.

So on the 15th annual Endangered Species Day, we reached out to some of our top wildlife photographers to see what scenes stuck with them through the years. Each is participating in a new project aimed at calling attention to the plight of endangered species around the world. Just as hunters once stalked the “big five”—the most dangerous animals to kill in Africa—photographers, filmmakers, conservationists, and the public are voting for their New Big 5: the threatened animals they shoot with a camera rather than a gun. (Learn more: What are Africa’s big five?)

For instance, photographer Ami Vitale chose to include a tender moment shared between an orphaned giraffe named Twiga and a wildlife keeper named Lekupinai. In the shot, the young giraffe nuzzles and kisses Lekupinai, giving us a glimpse of the bond that can form across species.

“Right now giraffe are undergoing what has been referred to as a silent extinction,” says Vitale, who has traveled to more than a hundred countries for her work. “Current estimates are that giraffe populations across Africa have dropped 40 percent in three decades, plummeting from approximately 155,000 in the late 1980s to under 100,000 today.”

Unfortunately, the long-necked animals are not alone. According to an United Nations report released last year, around a million species are now threatened with extinction. (Read more about what we lose when animals go extinct.)

The good news is that wildlife photography can be a powerful tool in the fight against extinction. After all, it helps ordinary people better understand and relate to animals they might never have the chance to interact with. And we can only save what we know—what we appreciate, what we love.

Take the pangolin. These critters are mammals, but they have thick scales like a reptile and sticky tongues longer than their body. Some species walk on their hind legs, holding their huge claws out in front of them like a tiny, termite-eating T. rex.

Sadly, thanks to demand for the animals’ meat and scales, pangolins are believed to be the most trafficked nonhuman mammal in the world. (Read more about the illegal pangolin trade.)

Pangolins are up-and-coming symbols of conservation, but photographer Jen Guyton says she still meets people who have no idea pangolins exist. But in just the last few years, that’s started to change.

“Visual storytellers are definitely contributing to that,” says Guyton, who is also an ecologist and National Geographic explorer. “I've gotten dozens of messages over the years from people who've told me they'd never heard of a pangolin before seeing my photos. Now many of those people are just as enraptured by these strange creatures as I am.”

“It couldn't be more important or more urgent to elevate these underdogs to the recognition they deserve,” she says.