Sorry Darwin, but it turns out promiscuity benefits females too

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Simone Rotella

I ONCE stole a lion’s girlfriend. At the time, I was in the Masai Mara in Kenya experimenting with audio playback as a means of deciphering lion communication.

This involved blasting a recording of a male lion’s roar into another’s territory and waiting for a response. Three lions – one female and two males – raced over to our Land Rover to investigate. The males quickly got bored when they failed to find anything that resembled a rival. The female, however, pinned the vehicle to the spot, legs akimbo, for over 2 hours. She was in oestrus and, in addition to mating with her consorts, she also wanted to mate with us. Not that this was anything special for the lioness: fertile females are known to mate 100 times with multiple males in a matter of days.

I was shocked and quietly thrilled to discover her licentious nature. At university, I was taught that males, with their endless supply of sperm, are wired for promiscuity, whereas females, with their limited number of eggs, must be choosy and chaste. Didn’t the lioness understand this “universal law”?

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My research since has exposed how sexist bias has been baked into evolutionary biology and warped our understanding of the female animal. We should remember that great scientists, even geniuses like Charles Darwin, are also people of their time. Darwin’s second great theoretical masterpiece – The Descent of Man, his book containing his theory of sexual selection – cast females in the role of the Victorian housewife: coy, submissive and invariant.

This theory of passivity was given an empirical lifeline in the 1940s by a British geneticist called Angus Bateman, whose legendary fruit fly mating experiment “proved” that females have little to gain from multiple mating, whereas males do. Bateman’s paradigm seared these deterministic sexual archetypes into evolutionary lore and crowned males as the dominant drivers of change.

The main trouble with this neat binomial classification is that it is wrong. Just ask the lioness. Her flagrant promiscuity is now understood to be a means of confusing paternity and protecting her offspring against the threat of infanticide by incoming males. This strategic sexuality was first discovered in langur monkeys by the primatologist Sarah Blaffer Hrdy in the 1970s, and has now been documented in dozens of species.

Hrdy leads a growing army of scientists keen to look beyond such misogynistic myopia and recognise the female of the species as just as promiscuous, aggressive, competitive and varied as the male. But what is shocking is how stubborn the stain of Victorian sexism is proving to be, and how far it has spread.

When Patricia Gowaty began doing DNA paternity tests on songbird eggs in 1984, she discovered that each nest frequently contained multiple fathers, despite the apparent monogamy of their parents.

Members of the male ornithological establishment responded by insisting the females had been “raped”. But radio trackers subsequently revealed females actively seeking sex with neighbouring cocks. Since then, a polyandry revolution has revealed that multiple mating is the norm for females, from lions to lizards. The reason is quite obvious: don’t put all your eggs in one basket – greater genetic diversity means healthier offspring.

Gowaty, like me, has never tried to hide her politics. She believes in equal representation of both sexes. But, as Darwin’s Victorian values show us, science is always political. A feminist perspective is urgently needed to topple centuries of androcentrism and rebrand female sexual agency, in lionesses or songbirds, from unexpected to a winning maternal strategy.

Lucy Cooke‘s new book is Bitch: A revolutionary guide to sex, evolution & the female animal @mslucycooke

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