Mr. Ben, a pygmy slow loris, is administed anesthetic during one of Bristol Zoo's in-house veterinary clinic routine health check-up and teeth clean as part of the Zoo's standard animal husbandry and welfare procedure at Bristol Zoo on June 18, 2009 in Bristol, England. (Photo by Matt Cardy/Getty Images)

Ace Wu searches the deep to photograph stunning underwater creatures. Against their predominantly black backdrops, Wu’s breathtaking subjects glow with sublime vibrancy. In one, a fearsome fish glares at the camera with rows of sharp teeth showing, while in another, a translucent octopus looks like an extraterrestrial. Here: Wunderpus larva. (Photo by Ace Wu/Caters News Agency)

A German Shepard bares its teeth during Schutzhund attack dog training at Witmer-Tyson Imports February 14, 2002 in Newark, CA. (Photo by Justin Sullivan/Getty Images)

Jean-François Leroy launched Visa Pour l’Image, the international photojournalism festival, in Perpignan in 1989. Before heading up the festival, Leroy was shooting reportage for the agency Sipa Press and also working for Photo-Reporter, Le Photographe, Photo-Revue and Photo Magazine. He is the chairman of the company Images Evidence. Photo: 2008 Visa d'or Feature: Brent Stirton. Conservation Rangers from an Anti-Poaching unit work with locals to evacuate the bodies of four Mountain Gorrillas killed in mysterious circumstances in the park, July 24, 2007, Virunga National Park, Eastern Congo. (Photo by Brent Stirton/Exclusive by Getty Images)

“Basunga”. Basunga (3 weeks-old newborn with albinism) is happily sleeping with his cousin. For now, he does not yet realize the difficulties he will face to integrate into the Congolese society as a PWA. The success of his integration will greatly depends of how he accepts himself and his skin condition a and how educated he will be. Photo location: Kinshasa, Congo RDC. (Photo and caption by Patricia Willocq/National Geographic Photo Contest)

A lioness bares its teeth inside an enclosure after a raid at a zoo-like house on the outskirts of Bangkok, Thailand Monday, June 10, 2013. Thai police and forestry officials searched and seized a number of imported and endangered animals including 14 lions from Africa and arrested the house's owner. (Photo by Apichart Weerawong/AP Photo)

“The Tasmanian devil (Sarcophilus harrisii) is a carnivorous marsupial of the family Dasyuridae now found in the wild only in the Australian island state of Tasmania. The size of a small dog, it became the largest carnivorous marsupial in the world following the extinction of the thylacine in 1936. It is characterised by its stocky and muscular build, black fur, pungent odour, extremely loud and disturbing screech, keen sense of smell, and ferocity when feeding”. – Wikipedia. Photo: A Tasmanian Devil bears it's teeth at a quarantine facility August 31, 2005 in Hobart, Australia. (Photo by Ian Waldie/Getty Images)

A boy looks inside the skull of a Tyrannosaurus Rex replica at the Egidio Feruglio Museum in Trelew, Argentina, in this May 18, 2014 file photograph. Scientists on July 28, 2015 unveiled a comprehensive analysis of the teeth of the group of carnivorous dinosaurs called theropods, which include the Tyrannosaurus Rex, detailing a unique serrated structure that let them chomp efficiently through the flesh and bones of large prey. (Photo by Maxi Jonas/Reuters)