Gelada baboons (Theropithecus gelada) play in their enclosure at the Zoo in Zurich, Switzerland, Wednesday, May 15, 2013. (Photo by Steffen Schmidt/Keystone/AP Photo)

Debris fly into the air as foreign fishing boats are blown up by Indonesian Navy off Batam Island, Indonesia, Monday, February 22, 2016. Authorities on Monday sank dozens of fishing boats caught operating illegally in Indonesian waters as part of the country's campaign to battle illegal fishing. (Photo by M. Urip/AP Photo)

Winton Elementary fifth graders Juliana Ragan, from left, Chloe Windsor and Paisley Ganske wait backstage for their turn to perform as the Andrew Sisters during the Pearl Harbor/Veterans assembly at the school on Monday, December 7, 2015, in Coeur d'Alene, Idaho. Dec. 7 is the 74th anniversary of the Japanese bombing of Pearl Harbor. (Photo by Kathy Plonka/The Spokesman-Review via AP Photo)

Yang Shiguang, 77, performs stunts at a park in Xi'an, Shaanxi province, September 3, 2013. Yang has been a member of a stunt performance club since 2007, after retiring from a research institution. (Photo by Reuters/China Daily)

Young female Ibex on the fork of Disteis (2,200 m), near the top of the Jof di Montasio (Friuli, Italy). (Photo by Stefano Zocca)

A child walks to an installation made from fallen leaves by college students, in shape of a sofa, to call for people's attention to environment protection, in Hangzhou, Zhejiang province, China, December 6, 2016. (Photo by Reuters/China Daily)

Chacha, the male chimp, screams at a worker in Sendai, northern Japan, Thursday, April 14, 2016 after fleeing from a zoo. The chimpangzee tried desperately to avoid being captured by climbing an electric pole. Chacha was on the loose nearly two hours Thursday after it disappeared from the Yagiyama Zoological Park in Sendai, the city that's hosting finance ministers from the Group of Seven industrialized nations in May. (Photo by Kyodo News via AP Photo)

These stunning pictures show a normally vicious tiger calmly swimming in a pool of algae, on Jule 9, 2014. The powerful cat takes a refreshing break by taking a dip in the bright green algae. But it looks like this big cat is scared of getting his head wet as he strains to keep it above the water. After splashing around for a bit the tiger gets out and tries to air-dry with specks of the vegetation dripping off his fur. The striking pictures were taken at Copenhagen zoo by snapper Soren Lundgren Neilson. (Photo by Soren Nielsen/Caters News)