A sculpture is displayed at the Olympic Sculptures Exhibition at the Sculpture Park September 4, 2006 in Changchun of Jilin Province, China. (Photo by China Photos/Getty Images)
A mahout removes the prosthetic from Motala, age 50, at the Friends of the Asian Elephant (FAE) elephant hospital in the Mae Yao National Reserve August 29, 2011 Lampang,Thailand. Motala lost a foot many years back after stepping on a land mine and now is on her third prosthetic, as they need to be changed according to the weight of the elephant. (Photo by Paula Bronstein/Getty Images)
New York Police Department tactical police officers stand guard near the New York Stock Exchange on September 9, 2011 in New York City. Officials are stepping up security in New York and Washington D.C. a day after U.S. officials received a credible but unconfirmed terror threat to utilize car bombs on bridges or tunnels in New York or Washington. (Photo by Justin Sullivan/Getty Images)
Actress Oh In-Hae and director Ahn Sang-Su arrives for the opening ceremony of the 16th Busan International Film Festival (BIFF) during the press conference at the Busan Cinema Center on October 6, 2011 in Busan, South Korea. The biggest film festival in Asia showcases 307 films from 70 countries and runs from October 6-14. (Photo by Chung Sung-Jun/Getty Images)
In animals, yawning can serve as a warning signal. For example, Charles Darwin, in his book The Expression of the Emotions in Man and Animals, mentioned that baboons yawn to threaten their enemies, possibly by displaying large canine teeth. Similarly, Siamese fighting fish yawn only when they see a conspecific (same species) or their own mirror-image, and their yawn often accompanies aggressive attack. Guinea pigs also yawn in a display of dominance or anger, displaying their impressive incisor teeth. This is often accompanied by teeth chattering, purring and scent marking.
People gather at the site of a bomb explosion in Sanaa December 23, 2014. Five bombs exploded on Tuesday in Sanaa's old quarter, where many supporters of the Shi'ite Muslim Houthi group live, killing at least one person and wounding another, a Yemeni security official said. No one has claimed responsibility for the attacks, but the Houthis have been fighting the Sunni Islamist militant al Qaeda group and allied tribesmen since its gunmen captured Sanaa in September and forced the resignation of a government they had long seen as corrupt. (Photo by Khaled Abdullah/Reuters)
A photographer has discovered a spectacular way of keeping warm during winter – using fire to heat up icy locations. Sam Scholes uses long-exposures to capture the movement of fire in front of ice-covered backdrops. After lighting steel wool his friend Scott Stringham swings the flaming object in order to make swirling patterns. The result of this technique – captured at Midway Ice Castles in Utah is a vibrant image with the warm light dancing across the cold scenes. (Photo by Sam Scholes/Caters News)
A member of the Community Police of the FUSDEG (United Front for the Security and Development of the State of Guerrero) poses with a weapon during events to mark the first anniversary of the force's operations in Ocotito, January 23, 2015. Based on the traditional indigenous justice system, the Community Police is made up of volunteers from different communities of Guerrero, and was created in response to the spate of violence in several locations in the state. (Photo by Jorge Dan Lopez/Reuters)