“In anatomy, heterochromia refers to a difference in coloration, usually of the iris (but also of hair or skin). Although infrequently seen in humans, complete heterochromia is more frequently observed in other species, where it almost always involves one blue eye”. – Wikipedia (Photo by StooMathiesen)

Two Herens cows lock horns during the qualification round of the annual “Battle of the Queens” cow fight finals in Aproz, in the western Alpine canton of Valais May 5, 2013. Each year when taken to the alpine pastures, the cows test their strength and fight for the herd's leadership. The competition continues until a new queen has forced all the other cows to retreat. (Photo by Valentin Flauraud/Reuters)

A keeper feeds a four-week-old jaguar while presenting it to the media, at a zoo in Ciudad Juarez, Mexico, October 14, 2015. (Photo by Jose Luis Gonzalez/Reuters)

A young Bengal tiger cub smuggled into the US and seized at the Mexico border is displayed for the media during Operation Jungle Book at the US Fish and Wildlife Service in Torrance, California on October 20, 2017. Operation Jungle Book, a law enforcement initiative led by the US Fish and Wildlife Service that targeted wildlife smuggling, resulting in federal criminal charges against defendants who allegedly participated in the illegal importation and/ or transportation of numerous animal species – including a tiger, monitor lizards, cobras, Asian “lucky” fish, exotic songbirds and several coral species. (Photo by Mark Ralston/AFP Photo)

A butterfly flies into the jaws of a crocodile inhabiting the Tarcoles River, the most polluted basin in Central America and one of the most polluted in Latin America, in the place of Tarcoles, province of Puntarenas, Costa Rica, 05 June 2018. Costa Rica, a country recognized worldwide for its environmental policies, seeks to be a leader in the replacement of single-use plastic with renewable and compostable alternatives, despite its lag in terms of recycling and integrated waste management. (Photo by Jeffrey Arguedas/EPA/EFE)

A black-winged stilt patrols a reservoir in Jezreel Valley in Israel early April 2023. Their eggs are a golden colour mottled with brown. (Photo by Itamar Procaccia/Solent News)

A little girl hangs three Siamese kittens on a washing line in a garden in Croydon, London. (Photo by Fox Photos/Getty Images). 14th July 1931

A caretta caretta pup is seen at Cirali Beach as they in a process of hatching and meeting the sea in Kemer district of Antalya, Turkey on July 22, 2020. 6 caretta caretta pups came out of the nest opened by the officials met the sea in the early morning. (Photo by Mustafa Ciftci/Anadolu Agency via Getty Images)