Believe it or not, pets have flexed their muscles by performing yoga for a calendar shoot. The felines and contorted canines are among the stars of the 2011 Yoga Puppies and Yoga Kittens calendars, British tabloid the 'Daily Express' reported. In fact, the tongue-in-cheek artwork was created by 53-year-old photographer Dan Borris. Relying on his wife Alejandra's skills as a yoga teacher, he gets her to hold and coax the pets into approximations of classic poses, then uses computer software trickery to make it look authentic. Dan, of San Antonio, Texas, insists that animal rights activists can relax, breathe and hold on to the thought that the pets are happy to go along with it. "Kittens and pups are very flexible but there's no forcing the animals to do anything," he was quoted as saying.