A photographer tested the concentration of several pairs of dogs as he captured their reactions to treat time in a series of shots. Christian Vieler, 47, of Waltrop, Germany, has been a professional dog photographer since 2016. He came up with the idea of snapping two dogs catching treats simultaneously. Here: Basset Hounds. (Photo by Vieler Photography/Caters News Agency)

It’s time to start watching for Comet PANSTARRS, one of two comets to get excited about in 2013. Photo: This image provided by NASA shoaws the comet PANSTARRS as seen from Mount Dale, Western Australia on March 5, 2013. According to NASA on March 10, it will make its closest approach to the sun about 28 million miles (45 million kilometers) away. As it continues its nightly trek across the sky, the comet may get lost in the sun's glare but should return and be visible to the naked eye by March 12. (Photo by AP Photo/NASA)

Laura Paipo (L), first blind principal in Uruguay participates in a street race with her sighted guide and friend Amparo Bauter in Montevideo, October 4, 2015. Paipo, 55, who took office on August 10, 2015 became the first blind principal of a special school which specializes in the education of visually impaired students. (Photo by Andres Stapff/Reuters)

King George V (1865–1936), king of Great Britain since 1910, with his queen-consort Queen Mary (1867–1953), at Collier Hospital on a visit to Dublin. (Photo by Topical Press Agency/Getty Images)

(L-R) Diana, Renata, Marina, Sveta and Anastasia of the Showtime reality show “Russian Dolls” visit “The Chaunce Hayden Show” on GFQ Network at Sapphire New York on August 17, 2011 in New York City. (Photo by Theo Wargo/Getty Images)

“Mario Armando Lavandeira, Jr. (born March 23, 1978), better known as Perez Hilton (a play on “Paris Hilton”), is an American blogger and television personality. His blog, Perezhilton.com (formerly PageSixSixSix.com), is known for posts covering gossip items about musicians, actors and celebrities. He is also known for posting tabloid photographs over which he has added his own captions or “doodles”. His blog has garnered negative attention for its attitude, its active “outing” of alleged closeted celebrities and its role in the increasing coverage of celebrities in all forms of media.” – Wikipedia

Photo: Blogger Perez Hilton poses with a wombat during a visit to Taronga Zoo on June 13, 2011 in Sydney, Australia. (Photo by Perezhilton.com via Getty Images)

Singer-songwriter Sheryl Crow meets Clyde the Sea Lion, the star of SeaWorld San Diego's “Sea Lion Tonite”, at the marine-life park's Sea Lion and Otter Stadium on August 3, 2011 in San Diego, California. Crow and her sons spent the day a SeaWorld meeting, feeding and learning about sea turtles, penguins and sea lions, other park animal ambassadors. Crow was performing in San Diego on her summer concert tour with Kid Rock. (Photo by Mike Aguilera/SeaWorld San Diego via Getty Images)