A Sumatran Tiger looks at visiting children from it's enclosure during the ZSL London Zoo's annual stocktake of animals on January 5, 2015 in London, England. The zoo's annual stocktake requires keepers to check on the numbers of every one of the 800 different animal species, including every invertebrate, bird, fish, mammal, reptile, and amphibian. (Photo by Dan Kitwood/Getty Images)

A half-naked shrine parishioner using a wooden tub pours cold water onto himself during an annual cold-endurance festival at the Kanda Myojin Shinto shrine in Tokyo, Saturday, January 10, 2015. Pouring cold water on their bodies is believed to purify their souls. (Photo by Eugene Hoshiko/AP Photo)

Participants wearing costumes take part in the West Indian Day Parade in the Brooklyn borough of New York September 1, 2014. The parade, which draws a crowd of a million plus, celebrates Caribbean culture. (Photo by Eric Thayer/Reuters)

Chincoteague Ponies swim across Assateague Channel in a heavy downpour on Wednesday, July 24, 2013 during the 88th Annual Chincoteague Pony Swim. A portion of the herd will be auctioned on Thursday. (Photo by Jay Diem/Eastern Shore News)

An Israeli soldier salutes as she attends a military cemetery ahead of the start of Remembrance Day at the graves of killed comrades on May 8, 2011 in Jerusalem, Israel. The 64th anniversary of the creation of Israel in 1948 has fallen on the Monday as determined by the Hebrew calendar and is preceded by the annual memorial recognising Israel's fallen soldiers. (Photo by Uriel Sinai/Getty Images)

Actress Tang Wei poses at the “Wu Xia” portrait session during the 64th Annual Cannes Film Festival on May 15, 2011 in Cannes, France. (Photo by Andreas Rentz/Getty Images)

A “jungle nymph” is measured during the annual weight-in ZSL London Zoo on August 21, 2014 in London, England. The height and mass of every animal in the zoo, of which there are over 16,000, is recorded and submitted to the Zoological Information Management System. This is combined with animal measurement data collected from over 800 zoos and aquariums in almost 80 countries, from which zoologists can compare information on thousands of endangered species. (Photo by Oli Scarff/Getty Images)

Yak near Yamdrok lake, Tibet. It is a long-haired bovinae found throughout the Himalayan region of south Central Asia, the Tibetan Plateau and as far north as Mongolia and Russia. The Tibetan economy is dominated by subsistence agriculture. Due to limited arable land, the primary occupation of the Tibetan Plateau is raising livestock, such as sheep, cattle, goats, camels, yaks, dzo, and horses. The Tibetan yak is an integral part of Tibetan life. (Photo by Dennis Jarvis)