Kumbuka, a male silverback gorilla sits next to the keeper's chalk board in his enclosure at London Zoo, Thursday, January 2, 2014. Home to more than 850 different species, zoo keepers welcomed in the New Year armed with clipboards as they made a note of every single animal. The compulsory annual count is required as part of ZSL London Zoo's zoo license, and every creature, from the tiny leaf cutter ants to the huge silverback gorilla is duly noted and accounted for. (Photo by Kirsty Wigglesworth/AP Photo)

A 42-day-old white bengal tiger cub (bottom), the first of its kind born in Peru, sleeps between toys as he is presented at the Huachipa's zoo in Lima on August 6, 2013. (Photo by Ernesto Benavides/AFP Photo)

A member of Four Paws International team carries a pelican to be taken out of Gaza, at a zoo in Khan Younis in the southern Gaza Strip August 23, 2016. Fifteen animals including a bengal tiger were removed from “the world’s worst zoo” in the Gaza town of Khan Younis as it was finally closed down. Animal welfare group, Four Paws International, will help bring most of the refugees to a zoo in Jordan, but the tiger will be taken to a refuge in South Africa. (Photo by Ibraheem Abu Mustafa/Reuters)

A Aldabra Tortoise receives a Christmas treat at Taronga Zoo on December 14, 2012 in Sydney, Australia. Taronga Zoo celebrated Christmas early giving Christmas-themed environmental activities to the Zoo's Giraffes, Sun Bears, Meerkats, Aldabra Tortoise and Cockatoos providing a wonderful natural display for Zoo visitors. (Photo by Lisa Maree Williams)

A freshwater stingray pup looks out from a holding tank at Bristol Zoo's aquarium on January 20, 2012 in Bristol, England. (Photo by Matt Cardy/Getty Images)

Bristol Zoo's baby gorilla Kukena holds onto his mother's arm as he ventures out of his enclosure at Bristol Zoo's Gorilla Island on May 4, 2012 in Bristol, England. The seven-month-old western lowland gorilla is starting to find his feet as he learns to walk having been born at the zoo in September. Kukena joins a family of gorillas at the zoo that are part of an international conservation breeding programme for the western lowland gorilla, which is a critically endangered species. (Photo by Matt Cardy)

Brazilian Tapir Tique is treated to a nice cold shower by the zoo keeper at Taronga Zoo on January 8, 2013 in Sydney, Australia. Temperatures are expected to reach as high as 43 degrees around Sydney today. (Photo by Marianna Massey)

In this Tuesday, June 18, 2013 photo, Zita, a liger – half-lioness, half-tiger – carries her one month-old liliger cub in the Novosibirsk Zoo. The cub's father is a lion, Sam. (Photo by Ilnar Salakhiev/AP Photo)