A man from Dinka tribe holds his AK-47 rifle in front of cows in a Dinka cattle herders camp near Rumbek, capital of the Lakes State in central South Sudan December 14, 2013. (Photo by Goran Tomasevic/Reuters)

A Humboldt penguin stands on weighing scales whilst being photographed by members of the press during a photocall at the annual weigh-in at London Zoo in London, Britain, 24 August 2016. Every animal that is in the zoo is weighed and measured and the statistics recorded so the data can be shared with zoos across the world. (Photo by Hannah McKay/EPA)

A handout photo made available by the World Press Photo (WPP) organization on 13 February 2017 shows a picture by Rossiya Segodnya photographer Valery Melnikov that won the Long-Term Projects – First Prize award of the 60th annual World Press Photo Contest, it was announced by the WPP Foundation in Amsterdam, The Netherlands on 13 February 2017. Caption: Civilians escape from a fire at a house destroyed by an air attack in the Luhanskaya village. (Photo by Valery Melnikov/EPA/Rossiya Segodnya/World Press Photo)

Shane Baker of Minnesota poses for a photo with adult film actress Rachel Starr at the Pornhub booth at the 2017 AVN Adult Entertainment Expo at the Hard Rock Hotel & Casino on January 18, 2017 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)

A hot air balloon floats over farm fields south of Washington, Ill., as the sun slips behind clouds on the autumn afternoon of Wednesday, September 24, 2014. (Photo by Ron Johnson/AP Photo/Peoria Journal Star)

In this June 17, 2014 photo, a North Korean man takes shelter in the rain next to long propaganda billboards in the town of Samjiyon in North Korea's Ryanggang province. The Associated Press was granted to embark on a weeklong road trip across North Korea to the country’s spiritual summit Mount Paektu. The trip was on North Korea's terms. An AP reporter and photographer couldn't interview ordinary people or wander off course, and government “minders” accompanied them the entire way. (Photo by David Guttenfelder/AP Photo)

Tanzania, 1964. A touching moment between primatologist and National Geographic grantee Jane Goodall and young chimpanzee Flint at Tanzania's Gombe Stream Reserve. (Photo by Hugo van Lawick via National Geographic)

These heart-warming photograph show an incredible bond between a wild lioness and the men fighting to save her species. The picture show Sirga – a 110lb lioness – and her adopted pride Valentin Gruener (not pictured) and Mikkel Legarth. Incredibly she treats the two men just like she would other lions and with their help she can now hunt for prey on her own. As a cub she was driven out from a pride and rescued by German and Danish duo Valentin and Mikkel who could not stand by and watch her die. She is now a beacon for hoped success of the Modisa Wildlife Project, founded in Botswana, Africa, by Valentin and Mikkel with the hope of saving the lion population. (Photo by Caters News)