“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)

A chevrotain or mouse deer feeds in its enclosure at Zurich Zoo, Zurich, Switzerland, October 17, 2012. (Photo by Patrick B. Kraemer/AP)

The goats are known to be good climbers, but this one is taking the climbing thing to a whole new level. It clambered on the tip of its owner’s stick, as a part of the roadside performance for a quick coin, on the outskirts of Faisalabad, Pakistan, November 5, 2012. (Photo by Fayyaz Hussain/Reuters)

A large Pacific sideband snail slowly crosses a rain wet road in rural Douglas County, Oregon near Elkton on Sunday, December 2, 2012. The moisture loving snail should be very content with the recent heavy rains in southwestern Oregon and northern California. (Photo by Robin Loznak)

A Aldabra Tortoise receives a Christmas treat at Taronga Zoo on December 14, 2012 in Sydney, Australia. Taronga Zoo celebrated Christmas early giving Christmas-themed environmental activities to the Zoo's Giraffes, Sun Bears, Meerkats, Aldabra Tortoise and Cockatoos providing a wonderful natural display for Zoo visitors. (Photo by Lisa Maree Williams)

New York's famed Empire State Building hosted new guests on Saturday night as images of endangered animals were flashed across its facade.

“Sniff out the Appenzell Cheese”. Alexander Hunter, 30, of Greenwich, Conn., took this photo in Appenzell, Switzerland, in September 2014. (Photo by Alexander Hunter)

It's often said that pets and their owners can start to look alike, but these adorable photographs take the old mantra to a new extreme. They are the work of Svetlana Valyiskaya (27), from St Petersburg, who snaps pets in everyday poses in her spare time from her job as a commercial photographer. The vibrant costumes and scenes, which Svetlana designs herself, have made the photos a hit in her native Russia – and it's not hard to see why. She said: “I really love animals, they are loyal, faithful and true and always interesting to work with – plus they never criticise the photographs afterwards”. (Photo by Svetlana Valyiskaya/Mercury)