Ancient Male Hominids Stayed At Home While Females Wandered

A just-published study in Nature suggests that our ancient female human ancestors were the ones who, on coming of age, left their social group for newer pastures. That is, ancient females were more likely to roam while ancient males stay closed to home, in contrast to the image we often have of females being the homebodies and males going out into the world.

Archaeological scientists analyzed the fossilized teeth ranging between roughly 1.8 million and 2.2 million years old from two South African caves. The teeth of the females were found to contain minerals from a different area than those of the males (which were distinguished from the females’ teeth due to their larger size).

Julia Lee-Thorp, an archaeological scientist at the University of Oxford, UK, and a co-author on the study, says that this is indeed “a very small clue,” but it is “at least hard evidence for what we really didn’t have before.” Nature describes the chemical analysis the scientists performed:

Lee-Thorp and her colleagues measured the levels of two isotopes of strontium, an element found in soil. This is taken up by plants and then snakes its way up the food chain into the growing bones of animals. The ratio of two strontium isotopes in bones or teeth provides a signature of the local environment in which an animal grew up, Lee-Thorp says. “It’s a kind of forensic tool.”

Her team measured the strontium isotope ratios in canine and third molar teeth — which are formed by about the age of eight — in eleven Paranthropus robustus individuals from the Swartkrans cave, as well as in teeth from eight Australopithecus africanus individuals from the nearby Sterkfontein cave, about 50 kilometres northwest of Johannesburg. The researchers also measured the strontium in 170 plants and animals currently living near the caves to get a sense of the different strontium signatures of the region, including the thin Malmani dolomite formation that includes both caves.

They discovered that larger teeth — ostensibly from bigger-bodied males — of both species were much more likely to share the strontium signature of dolomite-dwellers than the smaller teeth of female australopiths. About 90% of the larger teeth looked local, compared with less than half of the smaller teeth. The best explanation for this pattern is one in which females left their clan once they reached maturity, say Lee-Thorp and her colleagues.

While noting that the results of the study are fascinating, palaeoanthropologists and other scientists expressed caution, noting that the number of samples was not very large.

Supporting the study, Owen Lovejoy, an anatomist at Kent State University in Ohio, points out that “new males are likely to turn aggressive once they join a new group, risking the lives of infants and juveniles.” Thus, it would make more sense for males to stick with their social group of origin while females left home.

Another lead author of the study, University of Colorado at Boulder professor Sandi Copeland, notes in Science Daily that such a “female dispersal pattern,” with the females joining new social groups, is thought to exist in “two hominid groups is similar to that of many modern humans, chimpanzees and bonobos.” It is, though, unlike a pattern found in most other primates including gorillas, where “females stay with the group they are born into and the males move elsewhere.”

Lee-Thorp says that she is hoping to ask similar questions about early human ancestors, including our ancestors from East Africa and also later species of hominin, such as Homo erectus.

Finding out that males are the “original homebodies” does call into question assumptions such as a “woman’s place is in the home.” Wouldn’t it be something if our female ancestors were found to be the pioneering, adventuring spirits?


Photo of Australopithecus africanus from Wikimedia Commons.


Sarah M.
Sarah M.5 years ago

So cool.

Martha Eberle
Martha Eberle5 years ago

Interesting. When I first read the title, I was thinking it was referring to women being the hunters, but mightn't the conclusions mirror what women have done? -- leave their parents and cleave to their new mates, bringing them into new territories?

Teresa Wlosowicz
Teresa W.5 years ago

Women are not inferior to men in any respect. What right-wing politicians want to make as believe as the 'natural order' is nothing but patriarchal, misogynic propaganda!

Teresa Wlosowicz
Teresa W.5 years ago

Women are not inferior to men in any respect. What right-wing politicians want to make as believe as the 'natural order' is nothing but patriarchal, misogynic propaganda!

Teresa Wlosowicz
Teresa W.5 years ago

Women are not inferior to men in any respect. What right-wing politicians want to make as believe as the 'natural order' is nothing but patriarchal, misogynic propaganda!

Teresa Wlosowicz
Teresa W.5 years ago

Great article.

colleen p.
colleen p.5 years ago

i hate everything. it cut me off. "or are critters sexist like we are?"

colleen p.
colleen p.5 years ago

you people are all so fun. I will post again after reading everyone's comments.
the contrast of animal lovers and human equality folks make my day.

OK, so animals are on part with us, in all ways. Only they have differnt survival stragity.
but they think, feel and love and think and reason like we do. But if they don't, it is their nature, but they are still better than us

Humans are scum all over, with our own entitlements. men flog and brand women that are theirs, where as a noble elk wins women because he is strong.

other people had said again and again, the beings we are talking about are not humans. not Homosapians(or Homo sapians sapians?)

so to suggest they act like us, you should also say elk are terrible men, and any animal that has a harem is too.(although I saw on TV Zebra dads test suites after their daughters with a duel or something).

so, this species is sick bastard like our own, after 2 million years, who went "ugga ugga woman, ugga ugga want" and took it. We don't do it. it is wrong. Then again, few species are loveydovey monogamous, and if they are, there could be reasons for it. courtly love is new to our culture. or is it a step forward to ownership?
animals beat up other animal-males who go after their women. if they were nice, they would share.

I agree with the others. "someone is looking for a fantasy land". you might as well then say mayflies get married, or foxes have the highest divorce rate of all canids.

or are critters sex

colleen p.
colleen p.5 years ago

we are still animals, like the critters we share existing with. why would it be sexist or wrong to go "OH the women left ...blah blah blah". all of our cultures are differnt, and our symbolism. nature tells us when we are an adult, our cultures have rituals into adulthood, even if they body didn't kick start puberty.

some people are suggested to leave home at 18, some familes split up and children move far away. others abhor the thought of not having everyone be so strewn about. (unless is is purely for work?)

there are critter-animals who have males go off to find females in a new group. there are females who go off in hope of being accepted into a new group.

there are critters where both set off, and 'find eachother"(like the wolf)

Sharon Beth Long
Sharon Beth Long5 years ago

Even today in hunter-gatherer societies like the Bushmen upon reaching puberty girls move from group to group looking for a guy to "marry". Parents may want the sons who are necessary for hunting to stay close to home. Also less strong and less apt to fight females are seen as less of a threat to the power structure or leadership of other groups. Also,women are much more likely even in illiterate societies to try to maintain ties to the home base and especially to their mothers. I saw this even in graduate school where female foreign graduate students would write their families much more frequently than the male students. And on the other end of the spectrum females in complex hierarchical primate societies such as the chimpanzee and bonobo send out their females (I do not believe that gorillas are as intelligent) Thus, sending the females out tends to unite a society; if the males were sent out of the community it would fragment it. Like the saying goes "A son is a son until he takes a wife but a daughter is a daughter for all of her life".