U.S. President Barack Obama yawns as he sits between Japan's Prime Minister Yoshihiko Noda, right, and Chinese Premier Wen Jiabao during the plenary session of the 21st ASEAN (Association of Southeast Asian Nations) and East Asia summits in Phnom Penh, Cambodia on November 20, 2012. In his first meeting with a Chinese leader since his re-election, Obama said on Tuesday Washington and its chief economic rival must work together to "establish clear rules of the road" for trade and investment.

Alex Howe, 9, of Victorville, Calif,, right, yawns next to Sam T.E. Nitz, 13, of Costa Mesa, Calif., as they compete in the National Spelling Bee on Wednesday, May 30 in Oxon Hill, Md.

U.S. Naval Academy undergraduates yawn during graduation ceremonies which they are required to attend at the U.S. Naval Academy May 29 in Annapolis, Maryland. U.S. Secretary of Defense Leon E. Panetta was the commencement speaker for the 1099 graduates of the class of 2012.

A security guard yawns as he keeps watch at a gate of the Chaoyang Hospital, where blind human rights activist Chen Guangcheng is reported to be staying, in Beijing on May 7. Chen said on Monday he expected Beijing to let him and his family travel to the United States without fresh troubles, but he remained unsure of how long it would take for his travel arrangements to be made.

Ikar, a sniffer dog, yawns while riding with handler Vance McFarland, a Specialist of the U.S.Army 82nd Airborne Division, inside an armored vehicle outside Forward Operating Base (FOB) Pasab in Kandahar province, southern Afghanistan on May 26.

A hostess yawns while standing next to a Mercedes E Class Coupe at the Bucharest Auto Show in Bucharest, Romania, on April 4.

A job seeker yawns as he waits in front of the training offices of Local Union 46, a union representing metallic lathers and reinforcing ironworkers, in the Queens borough of New York on April 30. Some 500 people who have waited in front of the offices for a week after the State Department of Labor and the union announced that they were looking to hire iron and wood apprentices were given forms to apply for the 50 available positions on Monday, according to the union.

A penitent yawns while resting on crosses to be used during a re-enactment of the crucifixion of Jesus Christ on Good Friday in Iztapalapa in Mexico City on April 6.

A member of the audience yawns behind a copy of her program for the Franklin County Lincoln Day Dinner, where U.S. Republican presidential candidate and former Governor of Massachusetts Mitt Romney delivered remarks, in Greencastle, Pennsylvania on April 22

A member of the Occupy Wall Street movement yawns after waking up from a night of sleeping on the street in front of the New York Stock Exchange in New York on April 13.

A young penitent yawns while taking part in a Holy Thursday procession at Palma de Mallorca, on the Spanish Balearic island of Mallorca on April 5. Hundreds of processions take place around the clock in Spain during Holy Week, drawing thousands of visitors.

An Indian boy yawns as he stands on a concrete block to get a better view while watching a procession for Mahavir Jayanti, in New Delhi, India on Thursday, April 5. The holiday celebrates the birth anniversary of Lord Mahavira, who created the defining rules of Jainism.

Kentucky Derby hopeful Daddy Nose Best yawns as he gets a bath outside Barn 38 at Churchill Downs in Louisville, Ky. on Monday, April 30.