In this December 13, 2014 photo, Ricardo Alegria holds his donkeys by a leash as he yells to sell their milk in the streets of Santiago, Chile. Alegria, along with his brother Marco, has been selling fresh donkey milk for the past 25 years, and says it's recommended as a vitamin boost. Shot glass size cups of the drink sell for about $2 dollars. Half a liter, which is the most he says his donkeys can give in one day, sells for about $20 dollars. (Photo by Luis Hidalgo/AP Photo)

Camels walk down a street at the end of the Three Kings Day Parade in East Harlem on January 6, 2012 in New York City. (Photo by Mario Tama/Getty Images)

A Colombian Nukak Maku Indian boy gestures in a refugee camp at Agua Bonita near San Jose del Guaviare of Guaviare province September 3, 2015. Since emerging from the jungle in 2005, half naked and carrying blowpipes, the Nukak have lived in settlements near the frontier town of San Jose del Guaviare, a humid outpost in the Amazon 400 km (250 miles) southeast of the capital Bogota. (Photo by John Vizcaino/Reuters)

Giant panda Mei Xiang discovers a birthday cake meant for her cub Bei Bei (NP) who turns one at the Smithsonian National Zoo in Washington, DC on August 20, 2016. (Photo by Linda Davidson/The Washington Post)

Horses are spooked as the Woolsey Fire moves through the property on Cornell Road near Paramount Ranch on November 9, 2018 inAgoura Hills, California. About 75,000 homes have been evacuated in Los Angeles and Ventura counties due to two fires in the region. (Photo by Matthew Simmons/Getty Images)

A woman looks for fruits to buy inside a bus called Sacolao in Santa Teresa neighborhood in Rio de Janeiro, Brazil, July 7, 2015. The bus, which began operating as a municipal initiative but has been taken over by a private enterprise, arrives every week in some neighborhoods to facilitate families with their grocery shopping and sells food at an affordable price, according to sellers. (Photo by Pilar Olivares/Reuters)

A participant runs through foam during the Love Foam Run race in Hsinchu, Taiwan May 29, 2016. (Photo by Tyrone Siu/Reuters)

A day-old lamb exploring new surroundings on the vernal equinox, considered the first day of spring, on March 20, 2019 at Coombes Farm in Lancing, England. (Photo by Andrew Hasson/Getty Images)