An Israeli boy swims next to sheep belonging to a Palestinian farmer in the West Bank village of Al-Auja in the Jordan Valley on April 8, 2015 during the Jewish Passover holiday. Thousands of Israelis spent the day outdoors, picnicking and touring the country during the eight-day Passover holiday, which commemorates the Israelites' exodus from Egypt some 3,500 years ago. (Photo by Menahem Kahana/AFP Photo)

This artist image released from Japan's airline All Nippon Airways (ANA) on April 17, 2015 shows ANA's Boeing 787-9 aircraft into the colors of R2-D2 robot of Star Wars. Japanese air carrier ANA will place the special colored jetliner in service in this autumn. (Photo by AFP Photo/All Nippon Airways)

Elephants spray tourists with water in celebration of the Songkran water festival in Thailand's Ayutthaya province, about 80 km (50 miles) north of Bangkok, April 9, 2014. (Photo by Rungroj Yongrit/EFE)

Animal rights activists covered with fake blood sit on the floor during a protest against the use of animals in research to mark World Day for Animals in Laboratories in central Madrid April 24, 2014. The sign reads, “How many rabbits do your shampoo kill?”. (Photo by Andrea Comas/Reuters)

Firefighters pull a pig as they try to rescue it from a well at a pig farm in Huanghua township of Leqing, Zhejiang province, April 25, 2014. Seven local firefighters successfully rescued a 300 kg (661 lbs) pig which fell down a well on Friday morning, local media reported. (Photo by Reuters/China Daily)

An elephant “kisses” a visitor during a show at an elephant training school in Xishuangbanna, Yunnan province, April 18, 2015. Some 16 elephants live at the school and give four 30-minute performances everyday for visitors. (Photo by Wong Campion/Reuters)

Eduardo Alan of Argentina and Pampa Racing gets his Yamaha motorbike stuck in the sand during stage five of the 2012 Dakar Rally from Chilechito to Fiambala on January 5, 2012 in Fiambala, Argentina. (Photo by Bryn Lennon/Getty Images)

Nicole Scherzinger attends The BRIT Awards 2012 at the O2 Arena on February 21, 2012 in London, England. (Photo by Gareth Cattermole/Getty Images)