Darcin is a pheromone found in the urine of male mice. It's used to mark territory and signal mating availability, and was named after the character Mr. Darcy who appears in Jane Austin's Pride and Prejudice. In the new issue of Nature, researchers at Columbia University report on how darcin "takes hold in the brains of female mice, giving cells in the brain's emotion center the power to assess the mouse's sexual readiness and help her select a mate." From the press release: Pheromones, such as darcin, are processed somewhat differently.