A zoo keeper feeds Diego, a three month old howler monkey, which is reared at Edinburgh Zoo, July 29, 2008 in Scotland. (Photo by Jeff J. Mitchell/Getty Images)

A breeder puts a giant panda cub into a crib at Chengdu Research Base of Giant Panda Breeding in Chengdu, Sichuan province, September 23, 2013. Fourteen new joiners to the 128-giant-panda-family at the base were shown to the public on Monday, according to local media. (Photo by Reuters/China Daily)

Orphaned baby rhinos seen on August 28, 2014 in Lewa Wildlife Conservancy, Ngare Ndare Forest, Kenya. Lewa Wildlife Conservancy in Kenya is hand-raising three orphaned baby rhinos; Nicky, Hope and Kilifi. Baby rhino Hope was rescued by rangers when the poachers killed his mother – now he is been taken care off 24 hours-a-day at Lewa Wildlife Conservancy. The wildlife reserve hit the headlines when Prince William proposed to Kate Middleton there in 2010. Rhinos around the world are becoming extinct as a result of the brutal poaching fuelled by an illegal international market for their horns. (Photo by Luca Ghidoni/Barcroft Media)

Elephants feast on fruits and vegetables during the elephant buffet prior to the start of the 2016 King's Cup Elephant Polo event in Bangkok, Thailand, 10 March 2016. The annual charity event, now in its 14th edition, runs until 13 March and will involve 18 elephants brought from tourist trekking camps in Pattaya as well as some unemployed in Surin. A total of 10 teams encompassing over 40 players will take part in the event directed at raising funds to improve the lives of elephants and elephant conservation. (Photo by Diego Azubel/EPA)

Kenya Wildlife Service and Save The Elephants staff push an elephant as they undertake the collaring of ten elephants ranging near the Standard Gauge Railway to fit them with advanced satellite radio tracking collars in Tsavo National Park, Kenya March 15, 2016. (Photo by Goran Tomasevic/Reuters)

A mahout (elephant driver) walks a baby elephant across the city streets at night September 27, 2008 in Bangkok, Thailand. (Photo Paula Bronstein/Getty Images)

A mahout removes the prosthetic from Motala, age 50, at the Friends of the Asian Elephant (FAE) elephant hospital in the Mae Yao National Reserve August 29, 2011 Lampang,Thailand. Motala lost a foot many years back after stepping on a land mine and now is on her third prosthetic, as they need to be changed according to the weight of the elephant. (Photo by Paula Bronstein/Getty Images)