Fossil finger records key to Neanderthals' promiscuity

Nov 03, 2010
Neanderthals

(PhysOrg.com) -- Fossil finger bones of early human ancestors suggest that Neanderthals were more promiscuous than human populations today, researchers at the universities of Liverpool and Oxford have found.

Scientists, in collaboration with researchers at the universities of Southampton and Calgary, used finger ratios from fossilised of early apes and extinct hominins, as indicators of the levels of exposure species had to prenatal androgens – a group of hormones that is important in the development of masculine characteristics such as aggression and .

It is thought that androgens, such as testosterone, affect finger length during development in the womb. High levels of the hormones increase the length of the fourth finger in comparison to the second finger, resulting in a low index to ring finger ratio. Researchers analysed the finger bone ratios of and early apes, as well as hominins, Ardipithecus ramidus and Australopithecus afarensis, to further understanding of their social behaviour.

The clue's in the ring finger: a fossilied hand of an early modern human

The team found that the fossil finger ratios of Neanderthals, and early members of the human species, were lower than most living humans, which suggests that they had been exposed to high levels of prenatal androgens. This indicates that early humans were likely to be more competitive and promiscuous than people today.

The results also suggest that early hominin, Australopithecus - dating from approximately three to four million years ago - was likely to be monogamous, whereas the earlier Ardipithecus appears to have been highly promiscuous and more similar to living great apes. The research suggests that more fossils are needed to fully understand the social behaviour of these two groups.

Emma Nelson, from the University of Liverpool's School of Archaeology, Classics and Egyptology, explains: "It is believed that prenatal androgens affect the genes responsible for the development of , toes and the reproductive system. We have recently shown that promiscuous primate species have low index to ring finger ratios, while monogamous species have high ratios. We used this information to estimate the social behaviour of extinct apes and hominins. Although the fossil record is limited for this period, and more fossils are needed to confirm our findings, this method could prove to be an exciting new way of understanding how our social behaviour has evolved."

Dr Susanne Shultz, from the Institute of Cognitive and Evolutionary Anthropology at the University of Oxford said: "Social behaviours are notoriously difficult to identify in the fossil record. Developing novel approaches, such as finger ratios, can help inform the current debate surrounding the social systems of the earliest human ancestors."

The research is published in Proceedings of the Royal Society B.

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User comments : 17

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GreyLensman
3 / 5 (7) Nov 03, 2010
It's an enormous stretch to say that a broad rule of thumb (or fourth finger!) that applies to Homo Sapiens applies to any humanoid. In fact, it borders on the ridiculous.
TheQuietMan
3 / 5 (4) Nov 03, 2010
Agreed.
tkjtkj
5 / 5 (2) Nov 03, 2010
It's an enormous stretch to say that a broad rule of thumb (or fourth finger!) that applies to Homo Sapiens applies to any humanoid. In fact, it borders on the ridiculous.


Perhaps .. but the article did mention the author's having examined different primate species' correlations, although no data or ref's are given in this abbreviated article.
If every hooved animal we see is a quadruped, that a newly-discovered single hoof of a previously unknown species represents a quadruped is not any ridiculous conclusion.
Skeptic_Heretic
5 / 5 (3) Nov 03, 2010
It's an enormous stretch to say that a broad rule of thumb (or fourth finger!) that applies to Homo Sapiens applies to any humanoid. In fact, it borders on the ridiculous.

Except it appears to apply to all primates and is an established measure of social and cultural norms within the primate clades.
Sanescience
not rated yet Nov 03, 2010
Wonder how such studies compare more permissive cultures with restrictive ones. Say, like Sweden vs. Iran. Though reports on Iran suggest their promiscuous in their own way, with marriages only lasting hours to days.
plastikman
5 / 5 (3) Nov 03, 2010
My wife calls me a Neanderthal. Now I know why.
NickFun
5 / 5 (2) Nov 03, 2010
So...my lover can figure out how promiscuous I am before we even date by looking at my fingers??? Remind me to get my fingers shortened!
Mayday
5 / 5 (2) Nov 04, 2010
So, promiscuity is a masculine or male trait? I think these researchers need to get out more often.
jjoensuu
not rated yet Nov 06, 2010
If every hooved animal we see is a quadruped, that a newly-discovered single hoof of a previously unknown species represents a quadruped is not any ridiculous conclusion.


Yes that is in itself reasonable but it is ridiculous to say that just because we can draw conclusions about physical characteristics (such as amount of hoofs) from fossils, we should also be able to draw conclusions about behaviour from fossils.
ubavontuba
not rated yet Nov 06, 2010
I think there's a logical fallacy here. There seems to be an unfounded assumption that finger length is directly proportional to promiscuity and aggression. I can attest, there are plenty of exceptions. Some of the most gentle people I know have markedly short index to ring finger ratios and are also the biggest and most obviously masculine. They tended to have high birth weights and accelerated growth though, so I wonder if that might play a role (gentle giant syndrome?)?

Also, autism spectrum disorders are common in this group.

Perhaps an overabundance of prenatal androgens has even more profound effects than just increasing promiscuity and aggression. You know, sort of like how excessive steroid use makes a man ...well, less of a man.
Birthmark
not rated yet Nov 07, 2010
I totally see how this could be seen as ridiculous but the article does say
We have recently shown that promiscuous primate species have low index to ring finger ratios, while monogamous species have high ratios.

and that
[they] used this information to estimate the social behaviour of extinct apes and hominins.


So I think there may be some validity in this research, however there may be no real way of determining it.
Coldstatic
5 / 5 (1) Nov 08, 2010
So this is what i got out of the article, your finger length ratio does not determine your promiscuity. A low 2nd to 4th finger ratio implies that the mother, was more promiscuious while preggers with you. I think sexually active is a better word, but testosterone doesn't just show up during sex.
Ethelred
3 / 5 (2) Nov 22, 2010
Some of the most gentle people I know have markedly short index to ring finger ratios and are also the biggest and most obviously masculine.
That person is the Child of the promiscuous person in this study. They didn't come out and say it but the source of the testosterone is MEN and the place where it is having this effect is in the CHILDREN of the women. In other words its females that have sex while pregnant.

How accurate the study is depends on how many individuals were measured and how accurate their guesses were on which species were promiscuous.

Ethelred
Skeptic_Heretic
not rated yet Nov 22, 2010
So this is what i got out of the article, your finger length ratio does not determine your promiscuity. A low 2nd to 4th finger ratio implies that the mother, was more promiscuious while preggers with you. I think sexually active is a better word, but testosterone doesn't just show up during sex.
Correct, the pregnant woman could also be an occasional drinker during the pregnancy which would also serve to increase testosterone.
Ethelred
3 / 5 (2) Nov 22, 2010
Booze increased testosterone in women? I didn't know that.

I suspect the booze was in short supply for Neanderthals.

Ethelred
Skeptic_Heretic
not rated yet Nov 22, 2010
Booze increased testosterone in women? I didn't know that.

I suspect the booze was in short supply for Neanderthals.
You might be incorrect in that, but I don't know. Remember, we've had booze, or mash of some form for a long, long time, pre-egypt by some indicators. The research I'm citing is Jan 03 Alcoholism: Clinical & Experimental Research (for the testosterone piece, not the drunk neanderthal piece.)
Ethelred
1 / 5 (1) Nov 22, 2010
I am pretty sure that the diet of Neanderthal was largely that of a predator. Not much fermentable stuff around and no signs of containers to ferment stuff in.

The earliest recipe for beer used clay pots.

http://www.suite1...-a166734

http://www.nhm.ac...201.html

Funny how these articles both claim a varied diet. Meat, meat from land animals, meat from big animals, meat from little animals, meat from sea food. Pretty much seems to be vary from meat all the way to meat.

Well the mongols manage to ferment milk.

http://en.wikiped...ki/Kumis

Ethelred

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