A handout photograph provided by Brian Kubicki of Costa Rican Amphibian Research Center on 26 April 2016 shows a “Crystal frog”, Hyalinobatrachium dianae (H. diane). This frog was discovered by US biologist Brian Kubicki and Costa Ricans Stanley Salazar and Robert Puschendorf in a rainy forest of Costa Rican caribbean after 40 years without notice of any new example of this kind. (Photo by Brian Kubicki/EPA/Costa Rican Amphibian Research Center)

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)

Pakistani civil society activists release lanterns into the sky in Lahore on December 15, 2016, as they pay tribute to victims on the second anniversary of an attack on The Army Public School in the city of Peshawar. Taliban militants attacked on Pakistani Army Public School in Peshawar, killing 151 people mostly children on December 16, 2014. (Photo by Arif Ali/AFP Photo)

Seven year old Hungarian herding dog Derci runs along the Olympiaberg hill during stormy weather in Munich, southern Germany, Monday, January 4, 2016. (Photo by Matthias Balk/DPA via AP Photo)

Humboldt Penguins swim in their pool as a keeper looks on through a spherical window during the annual stocktake press preview at London Zoo in Regents Park in London Monday, January 4, 2016. A requirement of ZSL London Zoo's license, the annual audit takes keepers a week to complete and all of the information is shared with zoos around the world via the International Species Information System, where it's used to manage the worldwide breeding programmes for endangered animals. (Photo by Alastair Grant/AP Photo)

President Calvin Coolidge rides in a car during his inaugural parade in Washington, D.C., U.S. in March 1925. (Photo by Reuters/Library of Congress)

Poppy, a female Crowned sifaka, inspects a photographer's camera in the enclosure at the zoo of Mulhouse, eastern France, on March 5, 2019. The Crowned sifaka is a critically endangered species from Madagascar. (Photo by Sebastien Bozon/AFP Photo)

A four-week old southern three-banded armadillo (Tolypeutes matacus) is rolled up into a ball next to its mother in the tropical house of Budapest Zoo in Budapest, Hungary on May 3, 2019. The South American insect-eating mammal and its close relative, the Brasilian three-banded armadillo (Tolypeutes tricinctus) are the only two species of armadillos capable of rolling into a complete ball to defend themselves when feeling threatened. (Photo by Attila Kovács/EPA/EFE)