A leopard runs to at people as they run for cover in Katmandu, Nepal, on April 10, 2013. According to reports, 15 people were injured including three policemen and two officials from the Department of Forest. The leopard was later killed with the help of Nepalese policemen and local media. (Photo by Niranjan Shrestha/Associated Press)

ATTENTION: VISUAL COVERAGE OF SCENES OF INJURY AND DEATH

A goose has terrorized students at the University of Warwick, Coventry, UK, on May 22, 2013. The bird built its nest near a block of student apartments and attacks anyone who goes near the nest. (Photo by Caters News/The Grosby Group)

These two young siblings appear to cling on to a tree for dear life and even hold hands as they learn the ropes of climbing, on June 25, 2013. (Photo by Tim Fitzharris/Minden/Solent)

This handout photograph released by Taipei City Zoo on July 11, 2013 shows a newly-born panda cub of giant panda Yuan Yuan in an incubator at Taipei Zoo in Taipei. The public will have to wait three months to catch a glimpse of the first panda born in Taiwan, officials said after she was successfully delivered by parents who were gifted from China. (Photo by AFP Photo/Taipei City Zoo)

A four-month-old snow fox cub named “Vesna” (“Spring”) leaps next to a Zoo employee at the Royev Ruchey Zoo in Krasnoyarsk, Russia, on August 6, 2013. (Photo by Ilya Naymushin/Reuters)

A firefighter holds a red panda (Ailurus fulgens) from its tail while removing it from a tree at a residential area in Kunming, Yunnan province, July 3, 2014. The animal was spotted in the residential area and was brought down from the tree after residents reported its sighting to the police, local media reported. (Photo by Reuters/Stringer)

A man admires a sculpture in the series entitled 'Circle of Animals/Zodiac Heads' by Chinese artist Ai Weiwei in the courtyard of Somerset House on May 11, 2011 in London, England. The installation comprises of 12 bronze heads of animals which feature in the Chinese zodiac. The artist Ai Weiwei, who is outspoken in his criticism of the Chinese administration, was detained by authorities in Beijing on April 3, 2011 and his whereabouts remain unknown.

In this photo taken on Monday, January 5, 2015, a mallard duck attempts to walk on a frozen pond in Yukon, Okla. (Photo by Steve Gooch/AP Photo/The Oklahoman)