Polar bear Nanook plays with a ball as she celebrates her first birthday in the zoo in Gelsenkirchen, western Germany, Tuesday, December 4, 2018. (Photo by Marcel Kusch/DPA via AP Photo)





Bar-headed Geese, which migrate in winter from Central Asia and Tibet, fly at Nagrota Suriyan, about 65 kilometers (40 miles) south of Dharmsala, India, Thursday, November 29, 2018. The Pong Wetlands host and support hundreds of migratory bird species in the winter months. (Photo by Ashwini Bhatia/AP Photo)





A Mandarin duck walks in Central Park in New York, Wednesday, December 5, 2018. In the weeks since it appeared in Central Park, the duck has become a celebrity. (Photo by Seth Wenig/AP Photo)





Undated photo issued Friday November 30, 2018, by Dudley Zoological Gardens, showing snow leopard named Margaash which was euthanised after escaping from its enclosure at Dudley Zoo, in Dudley England. The eight-year-old animal escaped from its enclosure on Oct. 23, 2018, and was shot because the vet did not believe a tranquillizer dart was a safe option. (Photo by Dudley Zoological Gardens via AP Photo)





A rescued star tortoise, brought from Singapore, being kept at Bannergatta National Park in Bangalore, India on 27 November 2018. Reports state that over 50 Indian Star Tortoises were rescued in a repatriation mission launched by Wildlife SOS India and Animal Concerns Research and Education Society Singapore (ACRES) and they were brought to India from where they were originally smuggled from and sold into Singapore as victims of illegal wildlife trafficking. (Photo by Jagadeesh N.V./EPA/EFE)





A sambar deer looks on while trapped in a toilet stall of a school in the northern Indian hill town of Shimla on December 6, 2018. The adult deer was rescued by forestry department officials and released at a nearby nature reserve. (Photo by AFP Photo/Stringer)





Spiny mouses, one of the endangered animal species, are seen at the Bursa Metropolitan Municipality Zoo in Bursa, Turkey on November 29, 2018. These spiny mouses are generally found in Turkey's Mersin provinces and around Silifke and Cukurova districts. (Photo by Ali Atmaca/Anadolu Agency/Getty Images)





A Van cat, with two different eye color, is seen at Van Cat Research Center of Yuzuncuyil University in Van, Turkey on December 5, 2018 in Van, Turkey. Van cats can be categorized according to the color of their eyes and their fur. While some feature mismatched eyes, with one blue and the other amber, others have two blue or amber eyes. Also, while some have completely white fur, others have a dash of brown above their ears, head, or on their body. Citys most important living cultural heritage's population increase 15 % all the year round (Photo by Ozkan Bilgin/Anadolu Agency/Getty Images)





A swan preens its feathers at Melbourne's Port Phillip Bay on December 5, 2018. (Photo by William West/AFP Photo)





Balinese long-tailed monkeys, Macaca fascicularis, are pictured in the Sacred Monkey Forest in Ubud, Bali, Indonesia, on November 16, 2018. (Photo by Gabriel Bouys/AFP Photo)





A Sumatran tiger cub plays with its mother at Jihlava zoo in Jihlava, Czech Republic on November 27, 2018. (Photo by Slávek Růta/Rex Features/Shutterstock)





A dog is seen in a fashion exhibition during the seventh edition of the “Mi Mascota” (My Pet) fair in Malaga, southern Spain November 24, 2018. (Photo by Jon Nazca/Reuters)





General view of a dog wearing an England shirt outside the stadium before the Quilter International match between England and Australia on November 24, 2018 in London, United Kingdom. (Photo by Toby Melville/Reuters)





Dead pilot whales are seen at the coast of Chatham Island, New Zealand, November 30, 2018, in this handout picture obtained by Reuters. (Photo by Department of Conservation New Zealand/Handout via Reuters)





This handout picture taken on June 23, 2016 and released by WWF-Australia and James Cook University shows a northern bettong (bettongia tropica) at a wildlife care house in Ravenshoe, Queensland. A truffle-eating Australian marsupial known as the rat kangaroo has suffered a dramatic population decline and could become extinct without urgent action to save the species, a report warned on December 6, 2018. (Photo by Stephanie Todd/James Cook University/WWF Australia/AFP Photo)





A tamed hawk attacks a rabbit during a traditional hunting contest in Almaty, Kazakhstan on December 2, 2018. (Photo by Pavel Mikheyev/Reuters)





A tamed hawk sits on a chair next to a participant during a traditional hunting contest in Almaty, Kazakhstan December 1, 2018. (Photo by Pavel Mikheyev/Reuters)





A great black hawk, a native of Central and South America, takes off with a gray squirrel at Deering Oaks Park, Friday, November 30, 2018, in Portland, Maine. Audubon has called it potentially the first record of the species in the U.S. (Photo by Robert F. Bukaty/AP Photo)





A cat sits under the Downing Street Christmas tree, in London, Britain, December 3, 2018. (Photo by Henry Nicholls/Reuters)





In this April 20, 2013 file photo, male greater sage grouse perform mating rituals for a female grouse, not pictured, on a lake outside Walden, Colo. The Trump administration is advancing plans to ease restrictions on oil and gas drilling and other activities on huge swaths of land in the American West that were put in place to protect an imperiled bird species. Land management plans released Thursday, Dec. 6, 2018, would open more areas to leasing and allow waivers for drilling pads to encroach into the bird's habitat. That would reverse protections for greater sage grouse enacted in 2015, under President Barack Obama. (Photo by David Zalubowski/AP Photo)