Basic Chimp-stinct: Older Females Preferred as Mates

Older women may lament the phenomenon of middle-aged men pursuing young hotties barely out of college; it's part of the human condition. But it seems female chimps have no such problems. Research published this week establishes that as far as chimpanzees go, age trumps beauty.

Chimp females get more sexually attractive to their partners as they age and anthropologists have found that male chimpanzees of all ages prefer the older, more experienced females as mates - and the older, the better.

The lead author of the study, Professor Martin Muller, said, "The normal stereotype is that females are choosy and males are promiscuous. And male chimps are fairly promiscuous, but we wanted to see whether they were exhibiting any kind of preference."

The ultimate findings were unambiguous. Male chimps most often approached older females for mating purposes. And the older the female chimpanzee was, the more likely a male chimp was to proposition her. This might be because of the social hierarchy of chimpanzee life as much as biology in that older females paired frequently with high-ranking males, and themselves inspired some of the most vicious contests between males who competed for the honor of mating with them.

Perhaps more interesting finding was about young female chimpanzees; they were not only less sexually attractive to chimp males of all ages, but they were actively avoided. Whether this was out of a sense of sexual revulsion or a chimp taboo aimed to prevent simian child-molestation is not clear.

Professor Muller theorized, "The very youngest adult, post-pubescent females are often avoided, and that just seems to be because, frequently, inexperienced mothers might lose their first infant. And also, the very youngest adult females just aren't very fertile yet."

So how can one explain this difference between human males and their nearest biological relatives?

The physiological differences between chimpanzees and humans might help explain the seeming inconsistency between humanity's quest for youth, and chimpanzee's quest for age and experience.

For example, human females undergo menopause as they get older, which rules out the chance of creating offspring. Chimpanzee females don't experience menopause, and are more fertile the older they get.

Even so, human socialization would seem to have pushed the preference for young women in their teens and early twenties past the point of biological explanation because women typically do not reach their reproductive or sexual peaks until their mid-to-late twenties and thirties, respectively.

Some blame monogamy; because humans mate for life, men may prefer a younger woman who can breed for a much longer time. Professor Muller adds fuel to that fire by saying, "Given that the human lineage evolved from a chimpanzee-like ancestor, they indicate that male preference for youth is a derived human feature, likely adapted from a tendency to form unusually long-term mating bonds."