Is there any scientific basis for “cougars”?

Perhaps:

Beginning in their late twenties, women face the unique adaptive problem of declining fertility eventually terminating at menopause. We hypothesize women have evolved a reproduction expediting psychological adaptation designed to capitalize on their remaining fertility. The present study tested predictions based on this hypothesis—these women will experience increased sexual motivations and sexual behaviors compared to women not facing a similar fertility decline. Results from college and community samples (N = 827) indicated women with declining fertility think more about sex, have more frequent and intense sexual fantasies, are more willing to engage in sexual intercourse, and report actually engaging in sexual intercourse more frequently than women of other age groups. These findings suggest women’s “biological clock” may function to shift psychological motivations and actual behaviors to facilitate utilizing remaining fertility.

Source: “Reproduction expediting: Sexual motivations, fantasies, and the ticking biological clock” from Personality and Individual Differences, Volume 49, Issue 5, October 2010, Pages 516-520