In this November 30, 2017 photo, Douglas scoops up mud from the bottom of the polluted Guaire River, in search of gold and anything valuable he can sell, in Caracas, Venezuela. Some stretches of the river smell of sewer while others emit a toxic odor of fuel, a stench that stays in ones nose for hours after leaving the water. (Photo by Ariana Cubillos/AP Photo)

Vice President of Lebanese Wildlife Alexandra Youssef, checks a fox at a vet clinic in Beit Mery, Lebanon on March 26, 2021. (Photo by Mohamed Azakir/Reuters)

A performer from the Imperatriz samba school takes part in the first night of Rio's Carnival at the Sambadrome in Rio de Janeiro on March 4, 2019. (Photo by Carl de Souza/AFP Photo)

A woman dressed as the Wizard of Oz’s Dorothy walks her dog dressed as the Cowardly Lion as they attend the annual Congressional Dog Costume Parade on Capitol Hill in Washington, DC, on October 27, 2021. (Photo by Jim Watson/AFP Photo)

“Double head vulture”. On the day of windy days during raptors migration some people in my country start to catch these tired raptors, so in this day we go to photograph some raptors and we saw these tow tired vultures, so we start to drag them away from the hunters until they reach a good hidden place, to make them safe until they start a new journey. Photo location: Kuwait. (Photo and caption by Mohd Khorshed/National Geographic Photo Contest)

A visitor takes in a view of the downtown district from Twin Peaks on Friday, January 9, 2015, in San Francisco. (Photo by Marcio Jose Sanchez/AP Photo)

People look at a black bear at the Chengdu zoo amid the coronavirus outbreak on March 26, 2020 in Chengdu, Sichuan Province of China. (Photo by Wang Lei/China News Service via Getty Images)

The secretive indri (Indri indri) of Madagascar, the largest living lemur. It is also critically endangered and highly evolutionarily distinct with no close relatives, which makes its branch one of most precarious on the mammal evolutionary tree. In the likely event that the indri goes extinct, we will lose 19m years of unique evolutionary history from the mammal tree of life. (Photo by Pierre-Yves Babelon/Aarhus University)