A handout photograph provided by Brian Kubicki of Costa Rican Amphibian Research Center on 26 April 2016 shows a “Crystal frog”, Hyalinobatrachium dianae (H. diane). This frog was discovered by US biologist Brian Kubicki and Costa Ricans Stanley Salazar and Robert Puschendorf in a rainy forest of Costa Rican caribbean after 40 years without notice of any new example of this kind. (Photo by Brian Kubicki/EPA/Costa Rican Amphibian Research Center)

A female hippopotamus named “Mali”, which means Jasmine, eats fruits arranged to look like a cake during her 50th birthday celebration at Dusit Zoo in Bangkok, Thailand September 23, 2016. (Photo by Chaiwat Subprasom/Reuters)

in Qayyarah, about 31 miles (50 km) south of Mosul, Iraq, Sunday, October 23, 2016.in Qayyarah, some 50 kilometers south of Mosul, Iraq, Sunday, Oct. 23, 2016. Islamic State fighters torched a sulfur plant south of Mosul, sending a cloud of toxic fumes into the air that mingled with oil wells the militants had lit on fire to create a smoke screen. (Photo by Marko Drobnjakovic/AP Photo)

A Black Pete interacts with children during the arrival of Sinterklaas, or Saint Nicholas, in Maassluis, Netherlands, Saturday, November 12, 2016. Sinterklaas and his helper Black Pete are at the center of a long-time controversy because Pete is often played by white people in blackface makeup. (Photo by Peter Dejong/AP Photo)

Tennis star Maria Sharapova poses with a Porsche 911 RSR race car at the 2016 Los Angeles Auto Show in Los Angeles, California, U.S November 16, 2016. (Photo by Mike Blake/Reuters)

Women take a selfie next to a police officer as they take part in New Year's Eve celebrations in the Bund, in Shanghai, China December 31, 2016. (Photo by Aly Song/Reuters)

Rapper Pitbull performs onstage during Nickelodeon's celebration of the new Burbank facility on January 11, 2017 in Los Angeles, California. (Photo by Charley Gallay/Getty Images for Nickelodeon)

Actress Kristen Schaal attends the 21st Annual Critics' Choice Awards at Barker Hangar on January 17, 2016 in Santa Monica, California. (Photo by Christopher Polk/Getty Images for The Critics' Choice Awards)