A wildlife ranger strokes a northern white rhino, only three of its kind left in the world, ahead of the Giant Club Summit of African leaders and others on tackling poaching of elephants and rhinos, Ol Pejeta conservancy near the town of Nanyuki, Laikipia County, Kenya, April 28, 2016. (Photo by Siegfried Modola/Reuters)

A layer of morning mist still covers the fields as the sun rises into the morning sky over Hohenfelden, Thuringia state, Germany, early 07 September 2016. Meteorologists predict the weather to become warm and sunny in the region with temperatures reaching around 256 degrees Celsius. (Photo by Martin Schutt/EPA)

A 6-week old Fennec fox, the smallest species of foxes, and a native to the Sahara desert in Africa, looks as its mother eats in the Ramat Gan Safari Park near Tel Aviv, Israel, Sunday, November 6, 2016. Sagit Horowitz, the safari spokeswoman said four Fennec foxes were born about six weeks ago. (Photo by Ariel Schalit/AP Photo)

In this Thursday, February 14, 2019, photo, a Transformer's Bumblebee mascot helps a woman carries paper bags at a shopping mall in Handan in north China's Hebei province. U.S. and Chinese envoys are holding a second day of trade talks after the top economic adviser to President Donald Trump said he has yet to decide whether to go ahead with a March 2 tariff increase on imports from China. (Photo by Chinatopix via AP Photo)

A veterinarian from the zoo of Besancon feeds “Soa”, a female crowned sifaka, in Besancon, eastern France, on February 18, 2019. The crowned sifaka is a critically endangered species from Madagascar. There were only 6 females over 20 individuals living in 7 zoos worldwide end of 2018. (Photo by Sébastien Bozon/AFP Photo)

A fan gestures next to a police officer while celebrating the life of British singer Keith Flint of techno group “The Prodigy” after his funeral in Braintree, Essex, Britain, March 29, 2019. (Photo by Henry Nicholls/Reuters)

Sudanese protesters rally outside the army complex in Sudan's capital Khartoum on April 18, 2019. Huge crowds of protesters thronged the Sudanese capital Khartoum today, a week after the army's ouster of president Omar al-Bashir, determined to complete their revolution seeking civilian rule. (Photo by Ozan Kose/AFP Photo)

As an airliner prepares to land, a bird takes off at the Gravelly Point park near Reagan National Airport in Arlington, Va. on December 23, 2018. (Photo by Michael S. Williamson/The Washington Post)