A crocodile at a zoo in the southern Taiwan city of Kaohsiung holds the forearm of a zoo veterinarian in its teeth, April 2007. Surgeons in Taiwan have reattached a vet's arm, after it was bitten off by a crocodile as he tried to give it an anaesthetic injection. His attacker is one of a pair of Nile crocodiles kept at Shoushan zoo. Nile crocodiles are known to be man-eaters, but are also listed as an endangered species. (Photo by Frank Lin/Reuters)

A brown bear waits for food at the zoo in Madrid, Spain on July 30, 2016. (Photo by Jorge Sanz/Pacific Press/SIPA Press/Rex Features/Shutterstock)

A spider monkey eats a mango at the Paraguana zoo in Punto Fijo, Venezuela July 22, 2016. Some 50 animals have starved to death in the last six months at one of Venezuela's main zoos due to chronic food shortages that have plagued the crisis-stricken South American nation. (Photo by Carlos Jasso/Reuters)

Solo, a rare baby tapir, makes his debut at Chester zoo, UK on July 18, 2016. The Malayan tapir is an endangered species and Solo is the first ever calf born at the zoo. (Photo by Chester Zoo/Rex Features/Shutterstock)

A newly born Mexican gray wolf cub, an endangered native species, is seen at its enclosure at the Museo del Desierto in Saltillo, Mexico, July 19, 2016. Though once held in high regard in Pre-Columbian Mexico, it is the most endangered gray wolf in North America, having been extirpated in the wild during the mid-1900s through a combination of hunting, trapping, poisoning and digging pups from dens. (Photo by Daniel Becerril/Reuters)

In this Tuesday July 12, 2016 photo, an elephant is lifted by a crane in an upside down position in Lilongwe, Malawi, in the first step of an assisted migration of 500 of the threatened species. African Parks, which manages three Malawian reserves is moving the 500 elephants from Liwonde National Park, this month and next, and again next year when vehicles can maneuver on the rugged terrain during Southern Africa's dry winter. (Photo by Tsvangirayi Mukwazhi/AP Photo)

Kea are the only true alpine parrots in the world and thrive as cunning opportunists in the freezing conditions of the Southern Alps. Kea are thought to have developed their wide array of food-finding strategies during the last great ice age, where they learned to adapt using their unusual powers of curiosity. (Photo by Tom Walker/BBC Pictures/The Guardian)

A runner tries to get the attention of a bull, named Santon, during the “Toro de Cuerda” (Bull on Rope) festival at Plaza de Espana square in Grazalema, southern Spain, July 18, 2016. Three bulls restrained by a rope are allowed to run through the streets of the village during the annual festival. (Photo by Jon Nazca/Reuters)