A six-day-old hippopotamus is pictured next to his mother, Kara, aged 21, on September 12, 2012 at “Planet sauvage” (“Wild planet”) Zoo in Port-Saint-Pere, western France. The birth, a rare event for this species in captivity, occured on September 7, 2012 in the Zoo. (Photo by Frank Perry/AFP Photo)

An elephant cools off at a zoo in Karachi, Pakistan, 31 March 2021. Caretakers at Karachi's zoo were working to keep animals cool during a​ heatwave affecting southern Pakistan. (Photo by Shahzaib Akber/EPA/EFE)

An Indian Royal Bengal tiger looks on at an enclosure on World Tiger Day at Alipore Zoo, Kolkata, India, 29 July 2019. Kolkata zoo authority added a new Tiger to the zoo for the visitors to mark the Tiger Day. Students of Kolkata are also taking part in an awareness campaign aiming to draw attention to the threats that tigers face due to habitat loss and poaching. (Photo by Piyal Adhikary/EPA/EFE)

Sandra, a 29-year-old orangutan at Buenos Aires' zoo, on May 20, 2015. Sandra got cleared to leave a Buenos Aires zoo that was her home for 20 years, after a court ruled she was entitled to more desirable living conditions. (Photo by Juan Mabromata/AFP Photo)

Two three-month-old female white Bengal tiger cubs play with a zoo keeper in their enclosure at the Buenos Aires' Zoo, in Argentina, on April 17, 2014. Captive white Bengal tiger Cloe, gave birth to three cubs – two females and one male – on January 14, 2014. (Photo by Juan Mabromata/AFP Photo)

A young visitor interacts with a baby hippopotamus swimming in its enclosure at the Berlin Zoo on January 1, 2018. Tourists and locals flocked to the zoo in the German capital on the unseasonably warm first day of the year. (Photo by Odd Andersen/AFP Photo)

A South China Tiger cub meets public at Guangzhou Zoo on June 22, 2017 in Guangzhou, Guangdong Province of China. Guangzhou Zoo boasts of the successful breeding of South China Tiger cub after 15 years. (Photo by VCG/VCG via Getty Images)

An elephant with a shackled leg is pictured at the Hanoi Zoo in Hanoi on August 16, 2023. Legs in iron chains and unable to roam freely, the treatment of two elderly elephants at the Hanoi public zoo has drawn outrage from animal lovers across Vietnam. (Photo by Nhac Nguyen/AFP Photo)