Two stags fight in a wildlife park in Aurach near Kitzbuehel, in the Austrian province of Tyrol. (Photo by Kerstin Joensson/Associated Press)

A Kazakh hunter walks with his tamed golden eagle during an annual hunting competition in Chengelsy Gorge, some 150 km (93 miles) east of Almaty February 22, 2013. (Photo by Shamil Zhumatov/Reuters)

Two carnival revellers masquerade as Leonardo da Vinci's painting “Mona Lisa” pose in St. Mark's Square in Venice, Italy, Sunday, January 31, 2016. Carnival-goers in Venice are being asked by police to momentarily lift their masks as part of new anti-terrorism measures for the annual festivities. (Photo by Domenico Stinellis/AP Photo)

Barny, the Harveys Brewery dog has a sniff of a pint of beer at the Great British Beer Festival, at Olympia in London, Tuesday, August 11, 2015. The five day event is organised by the Campaign for Real Ale (CAMRA), with over 900 real ales, ciders, perries and international beers on offer. (Photo by Kirsty Wigglesworth/AP Photo)

A picture made available on 17 September 2014 shows extreme athletes resting in hammocks on webbings stretched between rocks during the International Highline Meeting in Monte Piana, near Misurina, in the northern Italian Alps, Italy, 08 September 2014. (Photo by Balazs Mohai/EPA)

An employee feeds a one-week-old coati cub with a bottle of milk at the Royev Ruchey zoo in the suburbs of Krasnoyarsk, Siberia, October 10, 2014. The mother of three cubs refused to nurse them, according to zoo employees. (Photo by Ilya Naymushin/Reuters)

A Miniature Dachshund (L) wears a duck bill-shaped dog muzzle while sitting in a stroller with another Miniature Dachshund at the “Interpets” international pet fair in Tokyo, Japan, April 2, 2015. (Photo by Kiyoshi Ota/EPA)

Young gymnasts practice pull-up on a bar at a gymnasium of a sports school in Jiaxing, Zhejiang province April 11, 2015. (Photo by William Hong/Reuters)