whenever i’m kinda tired and slightly braindead, i usually start trawling
the streets google books or online journals for any info/data on mating patterns in human populations. (unless i rewatch star wars for the umpteenth millionth time, obviously.) it’s my own, personal form of trainspotting just with less trains. and more mating patterns.
so i thought i’d share with you what i’ve got to date for sub-saharan (ss) african populations. this is faaar from being a complete list, nor is it systematic in any way. it’s just the stuff that i’ve happened to come across so far, so don’t read anything into the list like “overall there seems to be more inbreeding or outbreeding” or whatever.
first of all, there are a LOT of ss african populations! thousands. so, you know, it’ll take some time to get info on them all! here’s a map of the broad ethnolinguistic groups of africa that i’ve stolen from wikipedia — remember that there are hundreds if not thousands of subgroups within these broad groups:
needless to say, with such a wide variety of peoples, there is also a wide variety of mating patterns in ss africa. some populations avoid cousin marriage altogether. we’ve already seen this with the bamileke of cameroon and the igbo of nigeria. also the turkana of kenya and quite possibly the amhara of ethiopia (not 100% sure about them — need to double-check). a notable group which apparently avoids cousin marriage is the zulu. but plenty of other ss africa groups do practice cousin marriage like, as you’ll see in the table below, the kongo and luba in the democratic republic of congo, the ashanti in ghana, the sotho-tswana in south africa, and the kpelle of liberia. (fun fact that’s stuck in my brain for some reason — some of oprah’s ancestors were probably kpelle.)
the most common form of cousin marriage in ss africa is mother’s brother’s daughter (mbd) marriage which isn’t too surprising since that is the most common form of cousin marriage in the world. there’s an interesting twist to it in ss africa, though, thanks to all of the polygamy which is also very common in ss african societies. here from robin fox [pg. 195]:
“This latter form of marriage [mother's brother's daughter] is common in Africa and in patrilineal societies generally. Often, in Africa, it goes along with marriage to the wife’s brother’s daughter, as shown in diagram 4.2. A man either marries his wife’s brother’s daughter or passes the privilege on to his son (at least this is one way of looking at it). In many societies it is simply a straightforward privilege to marry the mother’s brother’s daughter.”
so, yeah, in case you were wondering, that would make the kids of these two wives (wife number one/aunt and wife number two/niece) both half-siblings and first cousins once-removed. and the children of wife number one are the first cousins once-removed to their father (and mother). and the children of wife number two are second cousins to their father. i think. i’ll let you think about it for a while. (~_^)
there is some father’s brother’s daughter (fbd) marriage (the type favored by the arabs) in some areas of ss africa — most notably amongst the hausa and fulani in northern nigeria, and the songhai and soninke in mali — but these are all muslim groups who i would guess picked up fbd marriage from the arabs/north african groups that introduced islam to them. youssef courbage and emmanuel todd think otherwise [pg. 43]:
“So-called Arab marriage, accepting union with any first cousin, but preferably with the father’s brother’s daughter, is not characteristic of sub-Saharan Africa. It is widely practiced only by the Fulani, nomadic herders of the northern fringe, immediately south of the desert, at a level so much higher than the Arab norm that it probably had an independent origin. It is also characteristic of some sedentary groups in the same area (Soninke in Senegal, Mali, and Mauritania; Songhai in Mali; Hausa in northern Nigeria). In West Africa, marriage is usually either exogamous or characterized by a preference for cross-cousin marriage, that is, between the children of a brother and a sister, a practice that has nothing to do with Islam.”
i don’t know if that statement about the fulani practicing a greater amount of fbd marriage than the arabs is correct or not. i shall have to try and find out. (here might be a good place to start.) i think it’s more likely that, being that the fulani have obviously been in contact with the arab/muslim world for quite a long time, they picked up the practice in that way. the afghanis and pakistanis also practice quite a lot of fbd marriage even though they’re at the edge of the “arabized” world, albeit at the other end of it, so i doubt that distance from arabia matters much here. it’s the contact with the greater arab world that counts.
two ss african groups that do seem to have adopted fbd marriage independently are the sotho-tswana and venda of south africa. need to learn more about those two groups. (note that the fbd marriage recorded in the table for the tutsi in rwanda refers only to some of the elites, not the general population.)
additionally, as in christian europe (especially medieval europe), some ss african groups prohibit marriage between in-laws — which is interesting. one example are the yao of malawi. they, however, happen to have a preference for cross-cousin marriage.
again, the other mating practice that is very common in ss africa is polygamy. i’ve said a few times here on the blog that you’d think that that would narrow the gene pool/relatedness between individuals in a group just as cousin marriage does. it might not always, though, because polygamy is not one thing either (can nothing ever be easy and straightforward?! (~_^) ). the lozi of zambia, for instance, apparently practice (or did traditionally) a sort of rapid serial polygamy, with wives being shuffled rather quickly on to the next husband, so that wouldn’t really narrow the genetic relatedness in the population at all, afaics. quite the opposite really. on the other hand, some groups practice sororal polygamy with the men making sure to marry sets of sisters, so that would narrow the relatedness in the group more so than a more basic form of polygamy in which men married women more randomly. the conclusion wrt polygamy, i think, is that each group will have to be evaluated on an individual basis. (*sigh*)
problem number one: for my purposes, since i’m interested in evolution and the selection of behavioral traits, i need to know how long populations have been inbreeding or outbreeding for, since natural selection does take some amount of time (but not necessarily millions of years). that’s difficult to work out for ss africans (and most of the world for that matter) without historic records or reams of genetic data which we haven’t got yet. it might be possible to reconstruct some of the history of mating patterns for some of the groups in ss africa from colonial accounts, especially those of missionaries who also acted as early ethnographers in many ways. we shall see. it would certainly be interesting to know for how long some of these groups have been inbreeding or outbreeding. as we’ve already seen, for instance, wikipedia claims that the igbo had a “quasi-republican” form of government in the 1400s with some sort of one-man-one-vote system. that’s not a system you find in heavily inbreeding societies — at least none that i can think of. what if it’s connected to the igbo outbreeding? dunno. Further Research is RequiredTM — and most likely it’ll have to be genetic.
problem number two: don’t have a whole lot of info on the rates of cousin marriage (or not) for most of these populations either. that’s also an extremely important detail to know. here are the few groups that i do have some numbers for:
- the fulani of burkina-faso: 65.8% first and second cousin marriage rate
- the fulani, mandinka, and wolof in gambia: 65% of first marriages of men are to a cousin – that’s an average of the three populations, and i don’t have a breakdown for each group
- the fouta-jallon (taramabli-dionfo) of guinea: 25.9% cousin marriage rate
- the yoruba of oka akoko in nigeria: 51.2% cousin marriage rate
- the lobedu (sotho) of south africa: 30% cousin marriage rate
so, there’s a variety in the rates, too. again, not surprising.
i think that’s it by way of the intro, so without further ado, here is my table. oh, the populations highlighted in yellow are those which include more than ten million people. and many of these groups spill over into other countries, of course, apart from the ones in which i’ve listed them [click on table for LARGER view - should open in new tab/window]:
i think that’s it for now! stay tuned. (^_^)
– A Companion to Ethics
– Consang.net – Table 1 – Consanguinity in Africa [pdf]
– Contingent Lives: Fertility, Time, and Aging in West Africa
– A Convergence of Civilizations: The Transformation of Muslim Societies Around The World
– Culture and Customs of South Africa
– Ethnic Groups of Africa and the Middle East: An Encyclopedia
– The Family Estate in Africa: Studies in the Role of Property in Family Structure and Lineage Continuity
– Joking, Affinity and the Exchange of Ritual Services Among the Kiga of Northern Rwanda: An Essay on Joking Relationship Theory
– The Making of the Pentecostal Melodrama: Religion, Media and Gender in Kinshasa
– Man in Africa
– Milk, Honey, and Money: Changing Concepts in Rwandan Healing
– Nomads who Cultivate Beauty: Wodaabe Dances and Visual Arts in Niger
– The Problem of Context
– Reproduction and Social Organization in Sub-Saharan Africa
– Seven Tribes of British Central Africa
– Slavery in Africa: Historical and Anthropological Perspectives
– The Social Basis of Health and Healing in Africa
– Structure and Sentiment: A Test Case for Social Anthropology
– Women and Marriage in Kpelle Society
– Women of Tropical Africa
previously: the bamileke of cameroon and fulani, hausa, igbo, and yoruba mating patterns and the turkana: mating patterns, family types, and social structures and ethiopia notes and
flatlanders vs. mountaineers revisited
(note: comments do not require an email. the yao of malawi. people will do the silliest things!)