It might be the sweet smell of success or the bitter whiff of despair, but there鈥檚 something in the odour of a male rat that tells a female whether he鈥檚 been copulating like crazy or starved of sex for days. And to make matters worse for frustrated males, the females much prefer the smell of road-tested studs.
Bennett Galef鈥檚 team at McMaster University in Hamilton, Ontario, Canada, placed two male rats behind mesh screens at either end of a tank, one of which had recently copulated with a female. A number of different female rats were then placed, separately, in the middle of the tank. Galef鈥檚 team found that these females typically moved over and lingered longer near the stud. When trials were repeated using female rats with no sense of smell, they showed no preference for either male (Animal Behaviour, ).
The study seems to illustrate the maxim 鈥渟uccess breeds success鈥�. It鈥檚 highly likely that the female rats are attracted by the smell of the sexually active male, rather than repelled by the stench of desperation from the sex-starved one, says Galef.
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鈥淚t鈥檚 unlikely that males would evolve a signal that makes them unattractive to females,鈥� he notes.
