A giant panda cub is pictured in an incubator at the Ya'an Bifengxia Giant Panda Breeding and Research Center in Ya'an city, southwest China's Sichuan province, 21 August 2015. Ten tiny panda cubs made their first public appearance at China's Ya'an Bifengxia Giant Panda Breeding and Research Center in southwestern Sichuan province on Friday (21 August 2015). All of the ten giant pandas were born in 2015. The oldest of them is just two month old, while the youngest one was born a week ago. This marks the first time they were put together as a group since they were born. (Photo by Imaginechina/Splash News)

A male deer barks at dawn during the annual deer rutting season at Richmond Park in London, Britain, October 9, 2016. (Photo by Toby Melville/Reuters)

People take pictures of deer in the Phoenix Park in Dublin, Ireland December 5, 2016. (Photo by Clodagh Kilcoyne/Reuters)

A wild leopard runs on the stairs as it tries to escape from a compound of a house in Kathmandu, Nepal June 1, 2016. (Photo by Navesh Chitrakar/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 gorilla cube named Pepe eats frozen fruit to fight high temperatures at the Bioparc zoo in Valencia, eastern Spain, 28 June 2019. Spanish peninsula is suffering a heat wave with temperatures reaching up to 45 degrees. (Photo by Kai Foersterling/EPA/EFE/Rex Features/Shutterstock)

A moon bear rests in a pool inside an enclosure at the Vietnam bear rescue centre, in Tam Dao national park, Vinh Phuc, Vietnam, 09 July 2019. The center is operated by international organization Animals Asia. There are currently 184 bears living at the the Vietnam Bear Rescue Centre. It is estimated that there are less than a few hundred bears left in the wild in Vietnam. According to the latest data from the Ministry of Agriculture and Rural development, around 600 bears are still being kept on farms. In Vietnam, Animals Asia has rescued a total of 209 sun bears and moon bears. (Photo by Minh Hoang/EPA/EFE/Rex Features/Shutterstock)

Leo, an orphaned Sumatran orangutan, is taken to the Sumatran Orangutan Conservation Programme rehabilitation centre. Leo will join other orangutans who have been reintroduced to the Pinus Jantho nature reserve. The SOCP has gradually formed a completely new wild population of species that have been threatened with extinction. (Photo by Sutanta Aditya/Barcroft Images)