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)

Hucul horses play in the wild meadows and forests near Odrzychowa in southeastern Poland on October 18, 2014. Huculs, a primitive breed of horse, escaped total extinction due to the efforts of scientists and Polish farmers. (Photo by Janek Skarzynski/AFP Photo)

A Nepalese Hindu devotee bathes in the Bagmati River on her way to the Pashupatinath Temple to offer prayers to Lord Shiva, Hindu god of destruction during Shravan festivities in Sundarijal, on the outskirts of Kathmandu on August 3, 2015. According to the Nepali calendar, Shravan is considered the holiest month of the year with each Monday of the month known as Shravan Somvar when worshippers offer prayers for a happy and prosperous life. (Photo by Prakash Mathema/AFP Photo)

Kritchaya “Lolita” Boonhor (R) curls her eyelashes in ladyboy Candy's (L) room while she chats her about her boyfriend, in Bangkok, Thailand, 27 November 2017. Most things in life are a question of negotiation. Lolita is a woman, that was not to be negotiated. What needed to be negotiated was how she was perceived by those around her. And that negotiation was one that took time and effort. (Photo by Lola Levan/EPA/EFE)

Firefighters pull a pig as they try to rescue it from a well at a pig farm in Huanghua township of Leqing, Zhejiang province, China, April 25, 2014. Seven local firefighters successfully rescued the 300 kg (661 lbs) pig, local media reported. (Photo by Reuters/China Daily)

In this Thursday, February 14, 2019, photo, a Transformer's Bumblebee mascot helps a woman carries paper bags at a shopping mall in Handan in north China's Hebei province. U.S. and Chinese envoys are holding a second day of trade talks after the top economic adviser to President Donald Trump said he has yet to decide whether to go ahead with a March 2 tariff increase on imports from China. (Photo by Chinatopix via AP Photo)

A veterinarian from the zoo of Besancon feeds “Soa”, a female crowned sifaka, in Besancon, eastern France, on February 18, 2019. The crowned sifaka is a critically endangered species from Madagascar. There were only 6 females over 20 individuals living in 7 zoos worldwide end of 2018. (Photo by Sébastien Bozon/AFP Photo)

General view of the Jacquemus Menswear Spring Summer 2020 show on June 24, 2019 in Valensole, France. (Photo by WWD/Rex Features/Shutterstock)