A sex pheromone named after Jane Austen's Mr Darcy sends female mice crazy with lust and makes them sing at ultrasonic frequencies, a study has found. Exposed to the special protein, dubbed 'darcin', in urine marks left by male mice, females displayed an immediate attraction and later began leaving their own markings. Both this and the singing are signs of an increased sex drive in mice. Discovered in 2010, the ...