Pet owners, at least in the West, are more likely than other people to be vegetarians or vegans. That puts many of them in a quandary when it comes to feeding fully paid-up carnivores such as cats and dogs. But technology may soon resolve this dilemma. The idea of growing meat for human consumption from scratch, in the form of cell cultures, is now becoming popular. Some see in this approach a way to produce guilt-free pet food, too. Among these visionaries are Shannon Falconer and Joshua Errett, the founders of Because Animals, a firm based in Philadelphia. They have taken the idea to what might be seen as its logical conclusion, for the starting point for their cultured cat food is that favourite feline prey, a mouse.