Visitors watch as Grigory Broverman, a member of the Cryophile winter swimmers club, pours a bucket of cold water over his 6-year-old daughter Liza during a flash mob, part of a celebration of Polar Bear Day at the Royev Ruchey Zoo in a suburb of the Siberian city of Krasnoyarsk, Russia, November 29, 2015. The air temperature was around minus 5 degrees Celsius. (Photo by Ilya Naymushin/Reuters)

A feeder trains a Siberian tiger cub at Erdaohe Tiger Park July 2, 2006 in Antu County of Yanbian Chaoxian Autonomous Prefecture, Jilin Province, China. About 15 artificially-fed Siberian tigers from Harbin Siberian Tiger Park are being trained to develop their ability to live in the wild. The wild Siberian tiger is listed as one of the most endangered species in the world, with its existing number estimated at around 400 worldwide, mainly in the northeastern part of China and the Far East of Russia. Reportedly there are more than 1,300 Siberian tigers which have been raised in China. (Photo by China Photos/Getty Images)

An undated handout picture released on January 10, 2017 by the Issekinicho publishing house shows an inter- species sexual behaviour between a male Japanese macaque and female sika deer, in Yakushima Scientists revealed on January 10, 2017 the “highly unusual” behaviour of a male monkey filmed trying to have sеx with female deer in Japan – a rare case of inter- species nookie. (Photo by Editions Issekinicho/AFP Photo)

The Kung Fu King was spotted in Botswana, Africa, as the two giraffes fought for dominance. Thomas Retterath, 53, says hes often seen the mammals fight, but they usually do it by banging their heads against each others bodies.Here: A giraffe lands a karate kick on a rival on the plains of Botswana. (Photo by Thomas Retterath/Caters News)

Almost two years old male baby orang-utan Dalai looks on in the zoo in Dresden, Germany, 30 March 2017. Dalai was born to mother Daisy in June 2016. (Photo by Filip Singer/EPA)

A dog with a cherry blossom-shaped pin, is seen in the cherry blossom festival in Seoul, South Korea, Sunday, April 9, 2017. (Photo by Lee Jin-man/AP Photo)

A mouse rides on the back of a frog in floodwaters in the northern Indian city Lucknow June 30, 2006. (Photo by Pawan Kumar/Reuters)