Black Live Matter march from Clapham Common (led by Iman, the Forever Family Force and the Slow Boys, on motorbikes) to join the Stop the Maangamizi: Afrikan Emancipation Day Reparations Rebellion in London, UK on August 1, 2020. They aim to lock-down Brixton because “WE/they are not being HEARD” in their demand for the UK Government to establish the All-Party Parliamentary Commission of Inquiry for Truth & Reparatory Justice. (Photo by Guy Bell/Alamy Live News)

Hundreds of volunteers stand at Goma International Airport receiving instructions before boarding a plane that will take them to a training center after responding to Democratic Republic of Congo's President Felix Tshisekedi's call to join the army to go to the front lines to fight against the M23 rebellion (March 23 Movement) in Goma, Democratic Republic of Congo, on November 14, 2022. (Photo by Guerchom Ndebo/AFP Photo)

Split-view of a killer whale at sunrise off the coast of Northern Norway. At least half of the world’s killer whale populations are doomed to extinction due to pollution of the oceans, a new study says. (Photo by Audun Rikardsen/Science)

Leo, an orphaned Sumatran orangutan, is taken to the Sumatran Orangutan Conservation Programme rehabilitation centre. Leo will join other orangutans who have been reintroduced to the Pinus Jantho nature reserve. The SOCP has gradually formed a completely new wild population of species that have been threatened with extinction. (Photo by Sutanta Aditya/Barcroft Images)

The tusk of a woolly mammoth that lived some 18,000 years ago, from which researchers sequenced the extinct mammal's entire genome, is seen in northeastern Siberia in this photo from 2015. (Photo by Love Dalen/Handout via Reuters)

Belgian animal sculptor Emmanuel Janssens Casteels works at his desk next to a replica of a Smilodon, an extinct genus of machairodont felid, in his workshop in Prayssas December 3, 2014. Casteels' company OPHYS specializes in life-size reconstructions and the sculpting or moulding reproductions of animals and hyper-realist fossils. His reconstructions are exhibited in museums and theme parks. (Photo by Regis Duvignau/Reuters)

Among the fish populations that could be harmed by the Xayaburi dam in Laos is the critically endangered Mekong giant catfish, considered by the Guinness Book of World Records to be the world’s largest freshwater fish. The fish, which grows to 650 pounds and about 10 feet long, is only found in the Mekong River. It is migratory, moving between downstream habitats in Cambodia upstream to northern Thailand and Laos each year to spawn. Some experts fear the Xayaburi dam could block the migration and drive the giant catfish to extinction. (Photo by Courtesy of Zeb Hogan/University of Nevada, Reno)