A ring-tailed lemur sunbakes at Melbourne Zoo in Melbourne, Victoria, Australia on December 21 2016. (Photo by Julian Smith/EPA)

Two sheep fight in a competition in Zhangjiakou, Hebei province, China on August 1, 2017. (Photo by Reuters/China Stringer Network)

A baby Sumatran orangutan is bathed after arriving at a wildlife center at Ratchaburi province in Thailand September 13, 2017. (Photo by Kerek Wongsa/Reuters)

19 giant panda cubs, all born this year, meet the public at the Shenshuping Base of the China Conservation and Research Centre for the Giant Panda on October 13, 2017 in Ngawa Tibetan and Qiang Autonomous Prefecture, China. So far China Conservation and Research Centre for the Giant Panda has successfully bred 42 giant pandas this year. (Photo by VCG/VCG via Getty Images)

This undated handout photograph released by Stony Brook University/ Louisiana State University on March 2, 2018, shows an Adélie penguin looking at a drone at breeding colony on Heroina Island, Danger Islands, Antarctica. A thriving “hotspot” of some 1.5 million Adelie penguins has been discovered on the remote Danger Islands in the east Antarctic, surprised scientists announced on March 2, 2018. (Photo by Rachael Herman/AFP Photo/Louisiana State University AND Stony Brook University)

The little new born wombat baby APARI sitting in its mothers pouch at the zoo in Duisburg, Germany, Thursday, March 29, 2018. Wombat mother TINSEL once was found in the pouch of its dead mother on a street in Australia and was raised by zookeepers before she came to Germany. The zoo tried for 40 years in vain to breed a wombat, until APARI was born as the first one last week. (Photo by Martin Meissner/AP Photo)

In this January 7, 2016, photo, conservationists of Borneo Orangutan Survival Foundation hold a baby orangutan rescued along with its mother during a rescue and release operation for orangutans trapped in a swath of jungle in Sungai Mangkutub, Central Kalimantan, Indonesia. Last year's forest fires drove orangutans closer to the river bank, where they had to live in an over-populated swath of forest as thin as 30 meters wide along the river. (Photo by Dita Alangkara/AP Photo)

A 6-month old female giant panda cub, an offspring of Xing Xing, formerly known as Fu Wa and Liang Liang, formerly known as Feng Yi, plays at the Giant Panda Conservation Center at the National Zoo in Kuala Lumpur, Malaysia, Thursday, February 18, 2016. (Photo by Joshua Paul/AP Photo)