These zoo animals take on an altogether more sinister look after posing for a set of moody black and white portraits. Alex Teuscher has brought out the dark side in a range of exotic creatures with his artistic project which took two years to complete. Photo: White tiger. (Photo by Alex Teuscher/BNPS)

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)

Sandra, a 29-year-old orangutan at Buenos Aires' zoo, on May 20, 2015. Sandra got cleared to leave a Buenos Aires zoo that was her home for 20 years, after a court ruled she was entitled to more desirable living conditions. (Photo by Juan Mabromata/AFP Photo)

In this photo taken on Monday, January 5, 2015, a mallard duck attempts to walk on a frozen pond in Yukon, Okla. (Photo by Steve Gooch/AP Photo/The Oklahoman)

A handout image released by the Taronga Zoo shows Veiled Chameleon hatchlings at Taronga Zoo in Sydney, Australia, 11 March 2015. Taronga has welcomed more than 20 baby chameleons, with the last of three clutches of eggs hatching this week. Veiled Chameleons, or Chamaeleo calyptratus, are native to Saudi Arabia and Yemen and can live up to five years. (Photo by EPA/Taronga Zoo)

Going toe-to-toe, these fighting primates could give Floyd Mayweather a run for his money. The amazing images – captured by Australian tourist Julie Rathbone on the banks of the Zambezi river in Africa – show the pair engaging in a few fisticuffs. The Chacma baboons appeared to settle a disagreement by fighting – before a senior baboon plays referee and steps in to break it up. Nurse unit manager Julie Rathbone, 59, from New South Wales, was on a cruise down the river when she spotted the fracas unfolding. (Photo by Julie Rathbone/Caters News)

In this Sunday, April 27, 2014 handout photo provided by Busch Gardens Tampa, mother armadillo Zowie, left, welcomes her newborn Southern three-banded armadillo baby at the Animal Ambassador Team, in Tampa, Fla. The baby was able to walk and roll into a ball within moments of its birth. Southern three-banded armadillos are the only species of armadillo that can fully roll up into a ball. (Photo by AP Photo/Busch Gardens Tampa)