The six-months-old female koala cub holds on to the back of zoo keeper Lena at the zoo in Duisburg, Germany, 23 October 2015. The yet unnamed baby weighs 580 grams. (Photo by Roland Weihrauch/EPA)

Jiejin Qiu, who is six months pregnant with her first baby, poses underwater during a photo shoot at a local wedding photo studio in Shanghai, in this September 5, 2014 file photo. (Photo by Carlos Barria/Reuters)

In this April 14, 2014 file photo, Hamamatou Harouna, 10, who lost the use of her legs to polio, crawls to the restroom on the grounds of the Catholic Church where she and hundreds of others found refuge after fleeing violence in her village, in Carnot, Central African Republic. Health authorities on Tuesday, August 25, 2020 are expected to declare the African continent free of the wild poliovirus after decades of effort, though cases of vaccine-derived polio are still sparking outbreaks of the paralyzing disease in more than a dozen countries. (Photo by Jerome Delay/AP Photo/File)

A Western Lowland Gorilla baby named “Mjukuu”, that was born in October last year, rides on the back of its Mother “Mbeli” in their enclosure at Taronga Zoo in Sydney, Australia, May 19, 2015. The baby gorilla was born six days ago, and is the second sired by the zoo's new Silverback, Kibali, who arrived from France in 2012. (Photo by David Gray/Reuters)

A woman carrying a child on her back looks at wigs on sale at the Baragwanath Taxi Rank in Soweto, South Africa, Wednesday, September 16, 2020. South African president Cyril Ramaphosa is scheduled to address the nation later in the day, as case numbers and death from COVID-19 hit the lowest in months. (Photo by Jerome Delay/AP Photo)

A Member of the Congress of South African Trade Unions (COSATU) joins other strikers as they take part in a nationwide strike over issues including corruption and job losses outside parliament in Johannesburg, South Africa, October 7, 2020. (Photo by Siphiwe Sibeko/Reuters)

A morgue attendant at the Johannesburg branch of the South African funeral and burial services company Avbob keeps the curtain open from inside a refrigerated container where bodies of patients deceased with COVID-19 related illnesses are kept isolated ahead of their burials on January 22, 2021. (Photo by Marco Longari/AFP Photo)

This photo provided by Netflix/naturepl.com and WWF-International shows an African Elephant (Loxodonta africana) in front of double rainbow, in Masai Mara, Kenya, included in the Netflix natural history series, “Our Planet”, in collaboration with Silverback Films and WWF. The eight-part series debuts in 2019. (Photo by Andy Rouse/Naturepl/WWF-International/Netflix via AP Photo)