A female hippopotamus named “Mali”, which means Jasmine, eats fruits arranged to look like a cake during her 50th birthday celebration at Dusit Zoo in Bangkok, Thailand September 23, 2016. (Photo by Chaiwat Subprasom/Reuters)

People follow king penguins exploring their outdoor pen, during a so-called “penguin parade”, when the animals walk outside their enclosure and the visitors can walk behind them, at Zurich's Zoo in Zurich, Switzerland January 28, 2017. (Photo by Arnd Wiegmann/Reuters)

A lemur licks a block of ice containing fruit at Rome's Bioparco zoo, Wednesday, July 5, 2017. Zookeepers at the Bioparco often give animals ice blocks with either fruit or meat on hot summer days. (Photo by Gregorio Borgia/AP Photo)

The owner of the zoo Pierre Thivillon laughs next to a chimpanzee on May 17, 2021, at the zoological park of Saint-Martin-la-Plaine, two days ahead of its reopening as part of France's latest step toward the ending of its third nationwide Covid-19 lockdown. (Photo by Jean-Philippe Ksiazek/AFP Photo)

A young child reaches out to a Gentoo penguin as it swims in its enclosure at Pairi Daiza Park in Cambron-Casteau, Belgium, Monday, July 5, 2021. Pairi Daiza, one of the biggest zoos in Europe, has recently added ten Gentoo penguins to their animal population. (Photo by Virginia Mayo/AP Photo)

A sun bear reacts to triple-digit temperatures at the Henry Doorly Zoo in Omaha, Nebraska, where the temperature reached 103 degrees Fahrenheit on July 6, 2012. (Photo by Nati Harnik/Associated Press)

Artist Elizabeth Thompson poses next to her Blu-tack Spider sculpture at London Zoo on October 25, 2007 in London, England. The sculpture, known as “Blu-ey”, is a model of a common house spider and is completely made out of blu-tack. It is on show at BUGS! at ZSL London Zoo. The sculpture is made from around four thousand packets of Blu-tack and weighs over 200kg. (Photo by Chris Jackson/Getty Images)

The world's biggest wild animal farmer, Carr Hartley of Rumuruti in Kenya, sells animals to zoos, circuses and film companies. (Photo by Maxim Ruston/BIPs/Getty Images). November 1956