Conspicuous animal signals attract both conspecifics and eavesdropping predators.We have well known that males with more attractive odor have higher mating success in rodents,but little empirical evidence tested whether more attractive rodents will face higher predation risk.Here,we used Lewis and BN (Brown Norway) rats of laboratory inbred strains and wild-captured rats as odor donors to test the correlation between male pheromone levels in rats and olfactory responses by domestic cats.Lewis rats have proved to have extremely higher levels of male pheromones (e.g.4-heptanone,2-heptanone and 9-hydroxy-2-nonanone) than BN rats,resulting in olfactory preferences of all females for Lewis male urine.