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)

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)

BASE jumper Luke Denniss of Australia gestures as he dives in the air from the Kuala Lumpur Tower during the KL Tower International Jump in Kuala Lumpur, Malaysia, Saturday, September 27, 2014. BASE stands for the places such jumpers usually jump from: buildings, antennas, spans (bridges) and earth (cliffs). (Photo by Lai Seng Sin/AP Photo)

An Oakland Raiders cheerleader performs during an NFL preseason football game against the Detroit Lions in Oakland, Calif., Friday, August 15, 2014. (Photo by Marcio Jose Sanchez/AP Photo)

The legs of camel and sheep for the “Living Nativity” scene, and Rockettes, of the “Radio City Christmas Special”, are juxtaposed as they pose for photos outside New York's Radio City Music Hall, Tuesday, October 28, 2014. The show is scheduled to open Friday, November 7, 2014 and continue through Wednesday, December 31, 2014. The “Living Nativity” has been part of the Christmas Spectacular since its inception in 1933. (Photo by Richard Drew/AP Photo)

Chinese artist Zhou Jie takes a nap on an unfinished iron wire bed, one of her sculpture works, after lunch as a friend of hers looks on at Beijing Now Art Gallery, in Beijing August 11, 2014. Zhou started her art project titled “36 Days” on August 9, in which she would live inside an exhibition hall with an unfinished iron wire bed, some iron wire sculptures in the shape of stuffed animal dolls, a certain amount of food and her mobile phone, for 36 days. The entire process is open to visitors and she may also interact with them, according to Zhou. (Photo by Jason Lee/Reuters)

A camel herder removes the rope from the mouth of a camel at the Pushkar Fair in Rajasthan, India, November 22, 2015. Thousands of animals, mainly camels, are brought to the annual fair to be traded. (Photo by Jitendra Prakash/Reuters)

Four-month-old fox cubs squaring up to each other in Walthamstow, England on August 7, 2015. (Photo by Greg Morgan/Barcroft Media)