"Who let the pups out?" Human pups, or people who dress up and act like playful puppies, are rapidly growing in numbers and confidence, spreading from the underground world of gay leather bars and bondage into a new and more mainstream “pup community”. Thousands of people around the world don dog-like hoods, tails and leather or rubber suits to indulge in puppy play and perhaps the most active puppy scene is in Britain, where organisers claim there are now up to 10,000 pups and handlers. Once confined to gay men, this “lifestyle hobby” is being taken up by women and straight men who are chasing non-sexual fun and relaxation. The author of the world’s only academic paper on puppy play, Liam Wignall of Sunderland University, says there has been a “fascinating shift from the original emphasis on dominance and submission towards a new focus on fun and escapism.” We speak to pups and their handlers, sexologists, psychologists and businesses involved in the world of human pups.