Human monogamy in mammalian context

Human monogamy in mammalian context | bioRxiv /* */ /* */ <!-- <!-- /*! * yepnope1.5.4 * (c) WTFPL, GPLv2 */ (function(a,b,c){function d(a){return"[object Function]"==o.call(a)}function e(a){return"string"==typeof a}function f(){}function g(a){return!a||"loaded"==a||"complete"==a||"uninitialized"==a}function h(){var a=p.shift();q=1,a?a.t?m(function(){("c"==a.t?B.injectCss:B.injectJs)(a.s,0,a.a,a.x,a.e,1)},0):(a(),h()):q=0}function i(a,c,d,e,f,i,j){function k(b){if(!o&&g(l.readyState)&&(u.r=o=1,!q&&h(),l.onload=l.onreadystatechange=null,b)){"img"!=a&&m(function(){t.removeChild(l)},50);for(var d in y[c])y[c].hasOwnProperty(d)&&y[c][d].onload()}}var j=j||B.errorTimeout,l=b.createElement(a),o=0,r=0,u={t:d,s:c,e:f,a:i,x:j};1===y[c]&&(r=1,y[c]=[]),"object"==a?l.data=c:(l.src=c,l.type=a),l.width=l.height="0",l.onerror=l.onload=l.onreadystatechange=function(){k.call(this,r)},p.splice(e,0,u),"img"!=a&&(r||2===y[c]?(t.insertBefore(l,s?null:n),m(k,j)):y[c].push(l))}function j(a,b,c,d,f){return q=0,b=b||"j",e(a)?i("c"==b?v:u,a,b,this.i++,c,d,f):(p.splice(this.i++,0,a),1==p.length&&h()),this}function k(){var a=B;return a.loader={load:j,i:0},a}var l=b.documentElement,m=a.setTimeout,n=b.getElementsByTagName("script")[0],o={}.toString,p=[],q=0,r="MozAppearance"in l.style,s=r&&!!b.createRange().compareNode,t=s?l:n.parentNode,l=a.opera&&"[object Opera]"==o.call(a.opera),l=!!b.attachEvent&&!l,u=r?"object":l?"script":"img",v=l?"script":u,w=Array.isArray||function(a){return"[object Array]"==o.call(a)},x=[],y={},z={timeout:function(a,b){return b.length&&(a.timeout=b[0]),a}},A,B;B=function(a){function b(a){var a=a.split("!"),b=x.length,c=a.pop(),d=a.length,c={url:c,origUrl:c,prefixes:a},e,f,g;for(f=0;f<d;f++)g=a[f].split("="),(e=z[g.shift()])&&(c=e(c,g));for(f=0;f<b;f++)c=x[f](c);return c}function g(a,e,f,g,h){var i=b(a),j=i.autoCallback;i.url.split(".").pop().split("?").shift(),i.bypass||(e&&(e=d(e)?e:e[a]||e[g]||e[a.split("/").pop().split("?")[0]]),i.instead?i.instead(a,e,f,g,h):(y[i.url]?i.noexec=!0:y[i.url]=1,f.load(i.url,i.forceCSS||!i.forceJS&&"css"==i.url.split(".").pop().split("?").shift()?"c":c,i.noexec,i.attrs,i.timeout),(d(e)||d(j))&&f.load(function(){k(),e&&e(i.origUrl,h,g),j&&j(i.origUrl,h,g),y[i.url]=2})))}function h(a,b){function c(a,c){if(a){if(e(a))c||(j=function(){var a=[].slice.call(arguments);k.apply(this,a),l()}),g(a,j,b,0,h);else if(Object(a)===a)for(n in m=function(){var b=0,c;for(c in a)a.hasOwnProperty(c)&&b++;return b}(),a)a.hasOwnProperty(n)&&(!c&&!--m&&(d(j)?j=function(){var a=[].slice.call(arguments);k.apply(this,a),l()}:j[n]=function(a){return function(){var b=[].slice.call(arguments);a&&a.apply(this,b),l()}}(k[n])),g(a[n],j,b,n,h))}else!c&&l()}var h=!!a.test,i=a.load||a.both,j=a.callback||f,k=j,l=a.complete||f,m,n;c(h?a.yep:a.nope,!!i),i&&c(i)}var i,j,l=this.yepnope.loader;if(e(a))g(a,0,l,0);else if(w(a))for(i=0;i (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0];var j=d.createElement(s);var dl=l!='dataLayer'?'&l='+l:'';j.src='//www.googletagmanager.com/gtm.js?id='+i+dl;j.type='text/javascript';j.async=true;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-M677548'); Skip to main content Home About Submit ALERTS / RSS Search for this keyword Advanced Search New Results Human monogamy in mammalian context View ORCID Profile Mark Dyble doi: https://doi.org/10.1101/2025.08.19.671116 Mark Dyble 1 Department of Archaeology, University of Cambridge , Fitzwilliam Street, Cambridge, UK , CB2 1QH Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Mark Dyble For correspondence: md479{at}cam.ac.uk Abstract Full Text Info/History Metrics Supplementary material Data/Code Preview PDF Abstract Monogamy has been argued to have played an important role in human evolution 1 – 5 and, across animals more generally, evolutionary transitions to highly cooperative societies have been far more likely to occur in monogamous species 6 – 8 , raising the possibility that this may also have been the case for humans. However, the extent to which we can consider monogamy to be the species-typical human mating system is subject to debate 9 – 11 . Here, I provide comparative context on human mating behaviour by comparing the distribution of sibling types (full siblings versus half-siblings) across >100 human societies with equivalent data from 35 nonhuman mammal species. While cross-culturally variable, rates of full siblings in humans cluster closely with rates seen among socially monogamous mammals and fall consistently above the range seen in non-monogamous mammals. Although the human data is demonstrative of cross-cultural diversity in marriage and mating practices, the overall high frequency of full siblings is consistent with the characterisation of monogamy as the modal mating system for humans. Main Text Evidence from birds 6 , mammals 8 , and insects 7 , 12 all suggest that transitions to eusocial or cooperative breeding systems are more likely to occur in monogamous species, raising the possibility that the evolution of highly cooperative social behaviour in humans was also preceded by the evolution of monogamy 11 , 13 . Additionally, many derived features of human biology and behaviour have been hypothesised to have co-evolved with a monogamous mating system, including increased paternal care 14 , extended post-reproductive lifespans 1 , and the recognition of extensive networks of kin 2 . Despite the hypothesised importance of monogamy in humans, the extent to which monogamy can be regarded our species-typical mating system has been subject to debate 9 , 11 , 13 . Although reduced sexual dimorphism 15 , reduced testes size 16 , and concealed ovulation 17 in humans have all been argued to be indicative of a transition to reduced levels of polygyny during hominin evolutionary history 11 , our ability to reconstruct mating systems from the fossil record is limited and focus has instead been on making inferences from the ethnographic record. Among contemporary or recent pre-industrial human societies, there is considerable diversity in marriage and mating norms and practices. For example, polygynous marriage (where a man is married to >1 woman at the same time) is permitted in ∼85% of a representative sample of pre-industrial societies 14 , 18 , leading to some to suggest that the predominance of monogamous marriage across much of the world today is an evolutionary novelty and a consequence of recent and rapid cultural change 9 . Others have argued that monogamy is a species-typical trait 19 and point out that even within societies that permit polygynous marriage, the majority of marriages are still monogamous 18 , 20 . Further complexity is added to human mating and marriage practices by the occurrence of serial monogamy 21 , polyandrous marriages 22 (where a woman is married to more than one man), partible paternity beliefs 23 , and extra-pair reproduction which is usually estimated to be <5% 24 but can be much higher 25 . An alternative but largely overlooked approach to assessing patterns of human mating is to consider the relative frequency full siblings, maternal half-siblings, and paternal half-siblings across populations 26 . At one extreme, exclusive lifetime reproductive monogamy (i.e. where an individual only ever reproduces with one other, who also only ever reproduces with them) would result in only full siblings, while random mating would result in many half-siblings and very few full siblings 27 . Here, I analyse data from a global sample of 106 human populations ( n = 197,695 sibling dyads in total) and compare this with a dataset of 35 nonhuman mammal species ( n = 61,181 sibling dyads). Data on nonhuman mammal species was compiled from a systematic literature search building on cross-species analyses of reproductive skew 28 and within-group relatedness 29 , 30 (see Methods). The dataset includes 10 species categorised as socially monogamous (defined as a species where a reproductive pair share a common range and associate with each other for more than one breeding season 31 ) and 25 species that are not socially monogamous (Supplementary Tables 1-2). The human data include ethnographic data on sibling proportions from ethnographic studies of kinship from 97 societies, including 80 from an existing dataset 26 as well as data from ancient DNA (aDNA) analyses of the genetic relatedness among individuals excavated from nine archaeological sites ranging in age from the Avar-period in Central Europe ∼1,100 years ago 32 to Neolithic Anatolia ∼8,000 years ago 33 (Supplementary Table 1). The proportion of siblings that are full siblings rather than paternal half-siblings or maternal half-siblings varied greatly across the human sample, from 26% among individuals excavated from an Early Neolithic site in Britain 34 to 100% of siblings in four populations, including a Neolithic cemetery from Northern France 35 . Across the entire human sample, the average proportion of siblings that are full siblings (66%) was comparable to the rates seen in socially monogamous nonhuman mammals (mean = 70.6%, range = 45.2% to 100%, n = 10) and consistently exceeded the range seen in the non-monogamous nonhuman mammals (mean = 8.3% of siblings are full siblings, range 0-22%, n = 25, Figure 1 ). As such, human mating patters produce sibling distributions that very clearly cluster with socially monogamous species such as meerkats ( Suricata suricatta , 59.0% full siblings) and African wild dogs ( Lycaon pictus , 85.0% full siblings) rather than non-monogamous species such as chimpanzees ( Pan troglodytes , 4.1% of siblings). Download figure Open in new tab Figure 1. Human sibling proportions in mammalian context. a , ternary plot showing the proportion of full siblings, maternal half-siblings, and paternal half-siblings across the sample of human societies and nonhuman species. b , boxplot showing the proportion of full siblings across the sample of human and nonhuman species. Boxplots show median values, 50th percentile values (box outline) and range (whiskers). Colours correspond to ancient human data (blue), ethnographic human data (grey), non-monogamous nonhuman mammals (orange), and monogamous nonhuman mammals (pink). Letters in circles are abbreviated species names (e.g. Oa = Ovis aries , Soay sheep, see Supplementary Tables 3-4). Although it is clear that random mating will result in very few full siblings and that exclusively monogamous mating will result in only full siblings, the nature of the relationship between extra-pair paternity and the proportion of full siblings is not obvious. In order to better understand this relationship, I constructed a computational model in which I varied rates of mating within a simulated population between exclusive monogamy (extra-pair paternity ( e ) = 0) and random mating ( e = 1) (Methods). Varying rates of e in this scenario produces a non-linear negative relationship between e (characterised as ‘extra-pair paternity’) and the proportion of full siblings ( Figure 2a ), with relatively modest rates of extra-pair paternity having a disproportionate effect on the production of half-siblings. For example, a 25% extra-pair paternity rate will result in only of ∼40% sibling dyads being full siblings, while 50% extra-pair paternity will result in ∼15% of siblings being full siblings ( Fig 2a ). Download figure Open in new tab Figure 2. Estimating extra-pair paternity from proportions of full siblings. a simulation results to estimate the proportion of siblings that are full siblings given varying rates of extra-pair paternity. Note that when e is high, the description of the parameter as extra-pair paternity is stretched because stable reproductive pairs cease to be present. Nonetheless, e captures the spectrum between exclusive monogamy and random mating. b estimated e for human and nonhuman mammal samples based on extrapolating observed sibling proportions through the predictions of the theoretical model. Although the exact relationship between extra-pair paternity and full sibling production is also influenced by group size, parity, and extra-group mating, the relationship is largely robust to these differences (see Extended Data Figure 2). Extrapolating back from the oberved rates of full siblings ( Figure 2b ), we can estimate e (extra-pair paternity) across the human sample to vary from 0 to 35%, averaging 12% ( Figure 2c ). Mean estimated rates produced for the monogamous and non-monogamous species are 9.9% and 69%, respectively ( Figure 2b ). A final means of comparing reproductive behaviour in humans with that of other species is to estimate rates of reproductive monogamy directly. This is here defined and measured as the proportion of reproductive individuals who have only reproduced with one individual and where that individual has themselves only reproduced with the focal individual. This is possible for a sub-sample of the total dataset for which parentage data are available (see Methods). An average of 61.0% of individuals across the ethnographic human datasets were reproductively monogamous ( n = 17 societies). Similarly, an average of 69.1% individuals across the sufficiently large archaeological samples ( n = 4) were reproductively monogamous. These rates are higher than seen in the nonhuman monogamous species (38.6%, n = 5) and much higher than seen in non-monogamous species (9.2%, n = 14, Figure 2 ). Discussion It has been hypothesised elsewhere that monogamy has played an important role in human evolution 2 , 3 , 13 , 36 , as well as in the evolution of highly social animal societies more broadly 6 – 8 , 12 . While previous work has relied on inferences from the fossil record 15 , or cross-cultural comparisons of marriage norms 10 , 18 , I here focus on the measuring the outcome of mating systems: the relative proportion of full and half-siblings born into a population; a direct, theoretically salient but relatively overlooked approach 26 . Although the variation in sibling composition across the human dataset is demonstrative of the obvious fact that humans are not universally monogamous, the finding that human rates of full siblings overlap with the range seen in socially monogamous mammal species and are consistently higher than those observed in non-monogamously mating mammal species lends weight to the broad-stroke characterisation of monogamy as the modal mating pattern for our species. If we can regard humans as a typically monogamous species, then we join the estimated minority of ∼9% of mammals that are socially monogamous 31 . However, where humans deviate from the vast majority of socially monogamous mammal species is that we live in social groups in which multiple females breed: socially monogamous mammalian species tend to either live in groups containing only the breeding pair and their offspring or in singular breeding groups where only one female of many reproduces 8 . Although monogamous pairs sometimes aggregate in a few species, the only other species of mammal that has been suggested live in stable multi-male multi-female groups containing multiple monogamous pairs is the Patagonian mara ( Dolichotis patagonum ), where large numbers of monogamous pairs may share a warren 31 , 37 . Humans also differ from most socially monogamous species in being monotocous 38 (i.e. typically producing single offspring per pregnancy rather than litters); all of the monogamous mammal species in the present sample, with the exception of the white-handed gibbon, are litter-bearing (polytocous) species (Supplementary Table 4). Therefore, while humans are not unusual among mammals in producing large numbers of full siblings through monogamous mating, we are unusual in doing so while being monotocous and living in plural breeding multi-male multi-female groups. Given that all other African great apes live in groups and have either have polygynous or polygynandrous mating systems, it is probable that human monogamy evolved from a non-monogamous group-living state, a transition that is highly unusual among mammals more generally 31 and which suggests different pressures selected for the evolution of monogamy in humans as compared to other species, possibly related to the energetic demands of our large brains and slow growth 39 , 40 . The “monogamy hypothesis” holds that the evolution of highly cooperative social behaviour is more likely to occur in species in which parents mate monogamously and produce full siblings 12 . The relevance of full siblings is that, in diploid species, individuals can expect to be as genetically related to their full siblings as they would be to their own offspring ( r = 0.5), more readily favouring altruistic behaviour toward kin and helping parents to raise younger siblings (‘helping at the nest’). The theoretical predictions about the relationship between extra-pair paternity and full sibling production shown here offer a refinement to this hypothesis because the non-linear relationship between extra-pair paternity and the production of full siblings suggests that even modest deviations from monogamy can have a large influence on diluting the proportion of siblings that are full siblings (e.g. ∼25% extra-pair paternity leads to ∼40% siblings as full siblings, though noting that the overall number of siblings of any kind also increases). This could go some way to explaining why, for example, the proportion of birds that are cooperative breeders (∼9%) is so much lower than the proportion that are socially monogamous (∼90%) 41 : it is not uncommon for socially monogamous birds have estimated rates of extra-pair paternity exceeding 20% 42 ; this may sufficiently reduce relatedness to make transitions to cooperative breeding unlikely. In humans, the majority of the half-siblings are paternal half-siblings rather than maternal half-siblings 26 . This is indicative of higher levels of male reproductive skew than female reproductive skew in humans 26 , 28 and is consistent with polygynous marriages being much more commonly permitted across human societies than polyandrous marriages, which are rare 18 , 43 . Since the ethnographic data are collected through self-reported parentage (see Methods) rather than genetic analysis, it is possible that there is some misattributed paternity within the ethnographic human dataset. However, the general consistency between genetic and ethnographic datasets in the frequency of full siblings suggests the effect may not be great and where extra-pair paternity has been estimated in human societies it is typically well under 5% 24 . Although a recent finding has reported 46% extra-pair paternity among Himba pastoralists 25 , this is a considerable outlier and was also accompanied by high paternity confidence; men were able to correctly identify whether they were the biological father of their spouse’s children in ∼75% of cases. It is important to note that what has been measured by analysing sibling proportions is patterns of reproduction, rather than patterns of mating and is therefore an assessment of reproductive monogamy, rather than monogamy in mating. In most mammals, mating and reproductive patterns will usually being tightly linked. In humans, this link will be diminished in part by birth control; not just the highly effective contraceptives developed over the last century but also ‘natural’ birth control methods and cultural practices to control fertility that are a consistent feature cross-culturally 44 , 45 . Human marriage and mating practices are highly variable, and there has been much interest in explaining this variability from an evolutionary perpective 9 , 46 , 47 . Here, I focus not on the variation but on general features of human mating in comparative mammalian context, concluding that monogamy can be regarded as the species-typical system for Homo sapiens . The value of such a generalisation is that it helps contribute to the assessment of the plausibility of hypotheses that have situated monogamy as a core human characteristic that has co-evolved with various aspects of our biology and behaivour 1 , 2 , 5 , 39 . If these hypotheses are correct, monogamy has played an important role in human evolution, allowing increased energetic investment and extended juvenility through paternal care that allow us to have more offspring at shorter intervals 39 and to establish the extended kinship networks (through the identification of paternal and affinal kinship 19 , 48 ) that provided the first step in building large-scale societies and cultural networks that have been crucial to our success as a species 49 . Methods Human dataset The human sample includes sibling proportions data from 106 human populations derived through archaeological or ethnographic data. The archaeological data are based on ancient DNA (aDNA) analyses of kinship from archaeological sites (Supplementary Table 1) 32 – 35 , 50 – 52 . To assemble this dataset, I conducted a literature search of journal articles on Web of Science with the search terms ‘(kinship OR relatedness OR genealogy) AND (aDNA OR ancient OR archaeological)’. I considered all papers returned up to and including July 2025 that included an arbitrary sample size threshold of at least 15 sibling dyads. This resulted in a sample of seven publications, two of which contained data on two separate archaeological sites with >15 sibling dyads: Wang et al. 32 included data from Avar-period cemeteries at Leobersdorf (90 sibling dyads) and Mödling-An der Goldenen Stiege (294 sibling dyads) while Gnecchi-Ruscone et al. 51 contained data from Rákóczifalva cemetery (165 sibling dyads) and Kunszallas-Fulopjakab cemetery (71 sibling dyads). Sibling relationships were calculated through assembling parentage lists from genealogical diagrams provided in the publications (Supplementary Table 1). Only sibling relationships between sampled (rather than genealogically inferred) individuals were included. The ethnographic data are built on genealogies compiled by ethnographers from a global sample of 97 pre-industrial human societies engaged in a range of subsistence types. Data on numbers of siblings for 80 of the 97 societies were included in an analysis by Ellsworth et al. 26 who compiled data through the open access kinsources database (kinsources.net) (N = 56 of 80), with additional information from two other publications 4 , 53 . I use the sibling proportion data tabulated by Ellsworth et al. 26 as well as sibling numbers for an additional 17 societies based on analysis of kinship datasets that have been made available through the kinsources project since 2016 (Supplementary Table 2). The categorisation of subsistence types was based on literature review and cross-referencing the society names with the DPLACE ethnographic database 54 . Although categorical distinctions between subsistence types are often somewhat arbitrary 55 , such categories are used here only to give an indication of economic diversity within the sample, rather than to test hypotheses about the relationship between dominant subsistence mode and sibling proportions. The similar proportions between the human genetic ( n = 9, mean full siblings = 65%) and genealogical data ( n = 97, mean full siblings = 66%) do not suggest a major discrepancy between the genealogically derived ethnographic and genetically derived archaeological datasets. Nonetheless, it is likely that some of the reported paternal relationships in the ethnographic dataset do not match genetic relatedness. To estimate the effect of possible underestimated extra-pair paternity on the results, I took the sample of 17 societies from the additional ethnographic dataset included here (Supplementary Table 2) and simulated extra-pair paternity by randomly replacing father names with those of a randomly sampled father at a given rate. The baseline proportion of full siblings averaging across these 17 societies in 69%, close to the overall mean for the ethnographic dataset of 66%. A simulated 1% extra-pair paternity rate reduces the proportion of siblings that are full siblings to 66.1%, a 3% extra-pair paternity rate reduces this to 62.6% and a 10% extra-pair paternity rate reduces this to 51.8% (Extended Data Figure 1). In all these scenarios these rates remain significantly higher than the rates seen in the non-monogamous mammal sample (range 0-22% full siblings, Extended Data Figure 1). Nonhuman mammal dataset While the mating systems of many of the >∼6,000 mammals species have been qualitatively classified 31 , data on sibling proportions requires genetic parentage analysis to have been conducted, something which has been done for a much more modest number of species. To restrict the sample to mammal species for which genetic data have been collected and where sibling data might therefore be available, I compiled a list of species that had been included in recent comparative studies of mammalian reproductive skew 28 and kinship composition 29 , 30 based on genetic data ( n = 70 species in total). For each of these candidate species, I followed up the references provided in the prior studies and complemented this with a Web of Science search for ‘[relevant species binomial] AND (siblings OR kinship OR paternity)’. These searches yielded 35 species for which sibling numbers could be determined, either because they were directly reported or because a parentage list was provided from which sibling distributions could be estimated (Supplementary Tables 3-4). In all cases, data come from a single study population with the exception of chimpanzees ( Pan troglodytes ) for which data were available for four populations (Supplementary Table 3; the species-level sibling numbers for chimpanzees are the sum of the numbers across these four populations). For categorical data on whether a species was socially monogamous, a plural or singular breeder, and monotocous or polytocous, species names were cross-referenced with published comparative analyses of plural breeding and monogamy in mammals 31 , 38 . Estimating sibling proportions and reproductive exclusivity Sibling proportions were estimated by calculating the numbers of individuals of known parentage who shared two parents (full siblings), a mother but had different fathers (maternal half-siblings), or a father but different mothers (paternal half-siblings). Reproductive exclusivity was calculated as the proportion of reproducing individuals (i.e., those who were represented in the dataset as the mother or father of at least one individual) who had reproduced with only one other individual who had themselves only reproduced with the focal individual. For this analysis the sample was necessarily restricted to those populations or species for which parent lists were available (all archaeological datasets, 17/97 ethnographic datasets, 20 of 35 nonhuman species datasets) with the five archaeological sites featuring fewer than 10 parents also excluded. Modelling sibling proportions The computational model was written in R 56 using custom code. The model starts by considering a group containing N f females who produce k offspring and then varying the extent to which they produce these offspring with one male versus multiple males. In the purely monogamous scenario (extra-pair paternity ( e ) = 0) there is exclusively monogamous mating and all siblings are full siblings. In the totally promiscuous scenario ( e = 1) males and females are randomly paired to reproduce and full siblings are rare. At intermediate rates (0 > e < 1), we start as in the exclusively monogamous condition and the father identity of each individual is then sampled to a random male with probability e . The model assumes a balanced sex ratio of potential mothers and fathers as well as all paternities falling within the group (though for relaxation of this assumption see Extended Data Figure 2). Estimation of e in the empirical data is based on taking the proportion of full siblings observed in each population/species and finding the simulation results that produced a proportion of full siblings within 2 percentage points of the observed proportion and taking the average value of e for those simulations. Data availability Sibling proportions for human populations and nonhuman species are provided in Supplementary Tables 1-4 and also available in an electronic format on GitHub. Where data on sibling proportions are constructed from parent lists, these are also available on GitHub ( https://github.com/mdyble/siblings.git ). Code availability Code for the estimation of sibling proportions based on parentage lists, production of figures, and simulations of sibling proportions are available on GitHub ( https://github.com/mdyble/siblings.git ). Author contributions M.D. compiled and analysed the data and model and wrote the paper. Competing interests The author has no competing interests to declare. Footnotes https://github.com/mdyble/siblings.git References 1. ↵ Coxworth , J. E. , Kim , P. S. , McQueen , J. S. & Hawkes , K. Grandmothering life histories and human pair bonding . Proc. Natl. Acad. Sci . 112 , 201599993 ( 2015 ). OpenUrl 2. ↵ Chapais , B. Monogamy, strongly bonded groups, and the evolution of human social structure . Evol. Anthropol . 22 , 52 – 65 ( 2013 ). OpenUrl CrossRef PubMed 3. ↵ Chapais , B. The deep social structure of humankind . Science 331 , 1276 – 7 ( 2011 ). OpenUrl Abstract / FREE Full Text 4. ↵ Hill , K. R. et al. Co-residence patterns in hunter-gatherer societies show unique human social structure . Science 331 , 1286 – 9 ( 2011 ). OpenUrl Abstract / FREE Full Text 5. ↵ Gavrilets , S. Human origins and the transition from promiscuity to pair-bonding . Proc. Natl. Acad. Sci. U. S. A . 109 , 9923 – 8 ( 2012 ). OpenUrl Abstract / FREE Full Text 6. ↵ Cornwallis , C. K. , West , S. A. , Davis , K. E. & Griffin , A. S. Promiscuity and the evolutionary transition to complex societies . Nature 466 , 969 – 972 ( 2010 ). OpenUrl CrossRef PubMed Web of Science 7. ↵ Hughes , W. O. H. , Oldroyd , B. P. , Beekman , M. & Ratnieks , F. L. W. Ancestral Monogamy Shows Kin Selection Is Key to the Evolution of Eusociality . Science 320 , 1213 – 1216 ( 2008 ). OpenUrl Abstract / FREE Full Text 8. ↵ Lukas , D. & Clutton-Brock , T. Cooperative breeding and monogamy in mammalian societies . Proc. R. Soc. B Biol. Sci . 279 , 2151 – 2156 ( 2012 ). OpenUrl CrossRef PubMed 9. ↵ Henrich , J. , Boyd , R. & Richerson , P. J. The puzzle of monogamous marriage . Philos. Trans. R. Soc. Lond. B. Biol. Sci . 367 , 657 – 69 ( 2012 ). OpenUrl CrossRef PubMed 10. ↵ Marlowe , F. W. The Mating System of Foragers in the Standard Cross-Cultural Sample . Cross-Cult. Res . 37 , 282 – 306 ( 2003 ). OpenUrl CrossRef Web of Science 11. ↵ Schacht , R. & Kramer , K. L. Are We Monogamous? A Review of the Evolution of Pair-Bonding in Humans and Its Contemporary Variation Cross-Culturally . Front. Ecol. Evol . 7 , ( 2019 ). 12. ↵ Boomsma , J. Lifetime monogamy and the evolution of eusociality . Philos. Trans. R. Soc. B Biol. Sci . 364 , 3191 – 3207 ( 2009 ). OpenUrl CrossRef PubMed 13. ↵ Kramer , K. L. & Russell , A. F. Was monogamy a key step on the hominin road? reevaluating the monogamy hypothesis in the evolution of cooperative breeding . Evol. Anthropol. Issues News Rev . 24 , 73 – 83 ( 2015 ). OpenUrl 14. ↵ Marlowe , F. Paternal investment and the human mating system . Behav. Processes 51 , 45 – 61 ( 2000 ). OpenUrl CrossRef PubMed Web of Science 15. ↵ Plavcan , J. M. Inferring social behavior from sexual dimorphism in the fossil record . J. Hum. Evol . 39 , 327 – 344 ( 2000 ). OpenUrl CrossRef PubMed Web of Science 16. ↵ Harcourt , A. H. , Harvey , P. H. , Larson , S. G. & Short , R. V. Testis weight, body weight and breeding system in primates . Nature 293 , 55 – 57 ( 1981 ). OpenUrl CrossRef PubMed Web of Science 17. ↵ Strassmann , B. I. Sexual selection, paternal care, and concealed ovulation in humans . Ethol. Sociobiol . 2 , 31 – 40 ( 1981 ). OpenUrl CrossRef 18. ↵ Murdock , G. & White , D. Standard cross-cultural sample . Ethnology 8 , 329 – 369 ( 1969 ). OpenUrl CrossRef Web of Science 19. ↵ Chapais , B. Primeval Kinship: How Pair-Bonding Gave Birth to Human Society . ( Harvard University Press , Cambridge, MA , 2008 ). 20. ↵ Binford , L. R. Constructing Frames of Reference: An Analytical Method for Archaeological Theory Building Using Hunter-Gatherer and Environmental Data Sets . ( University of California Press , Berkeley , 2019 ). 21. ↵ Borgerhoff Mulder , M. Serial Monogamy as Polygyny or Polyandry?: Marriage in the Tanzanian Pimbwe . Hum. Nat . 20 , 130 – 150 ( 2009 ). OpenUrl CrossRef PubMed Web of Science 22. ↵ Starkweather , K. E. & Hames , R. A Survey of Non-Classical Polyandry . Hum. Nat . 23 , 149 – 172 ( 2012 ). OpenUrl CrossRef PubMed 23. ↵ Walker , R. S. , Flinn , M. V. & Hill , K. R. Evolutionary history of partible paternity in lowland South America . Proc. Natl. Acad. Sci . 107 , 19195 – 19200 ( 2010 ). OpenUrl Abstract / FREE Full Text 24. ↵ Anderson , K. G. How Well Does Paternity Confidence Match Actual Paternity?: Evidence from Worldwide Nonpaternity Rates . Curr. Anthropol . 47 , 513 – 520 ( 2006 ). OpenUrl 25. ↵ Scelza , B. A. et al. High rate of extrapair paternity in a human population demonstrates diversity in human reproductive strategies . Sci. Adv . 6 , eaay6195 ( 2020 ). OpenUrl FREE Full Text 26. ↵ Ellsworth , R. M. , Shenk , M. K. , Bailey , D. H. & Walker , R. S. Comparative study of reproductive skew and pair-bond stability using genealogies from 80 small-scale human societies . Am. J. Hum. Biol . 28 , 335 – 342 ( 2016 ). OpenUrl 27. ↵ Dyble , M. Explaining variation in the kinship composition of mammal groups . Behav. Ecol . 35 , arae032 ( 2024 ). OpenUrl 28. ↵ Ross , C. T. et al. Reproductive inequality in humans and other mammals . Proc. Natl. Acad. Sci . 120 , e2220124120 ( 2023 ). OpenUrl 29. ↵ Pereira , A. S. , De Moor , D. , Casanova , C. & Brent , L. J. N. Kinship composition in mammals . R. Soc. Open Sci . 10 , 230486 ( 2023 ). OpenUrl CrossRef 30. ↵ Dyble , M. & Clutton-Brock , T. H. Contrasts in kinship structure in mammalian societies . Behav. Ecol . 31 , 971 – 977 ( 2020 ). OpenUrl CrossRef 31. ↵ Lukas , D. & Clutton-Brock , T. H. The Evolution of Social Monogamy in Mammals . Science 341 , 526 – 530 ( 2013 ). OpenUrl Abstract / FREE Full Text 32. ↵ Wang , K. et al. Ancient DNA reveals reproductive barrier despite shared Avarperiod culture . Nature 638 , 1007 – 1014 ( 2025 ). OpenUrl CrossRef PubMed 33. ↵ Yüncü , E. et al. Female lineages and changing kinship patterns in Neolithic Çatalhöyük . Science 388 , ( 2025 ). 34. ↵ Fowler , C. et al. A high-resolution picture of kinship practices in an Early Neolithic tomb . Nature 601 , 584 – 587 ( 2022 ). OpenUrl CrossRef PubMed 35. ↵ Rivollat , M. et al. Extensive pedigrees reveal the social organization of a Neolithic community . Nature 620 , 600 – 606 ( 2023 ). OpenUrl CrossRef PubMed 36. ↵ Lovejoy , C. O. The Origin of Man . Science 211 , 341 – 350 ( 1981 ). OpenUrl Abstract / FREE Full Text 37. ↵ Taber , A. B. & Macdonald , D. W. Spatial organization and monogamy in the mara Dolichotis patagonum . J. Zool . 227 , 417 – 438 ( 1992 ). OpenUrl CrossRef Web of Science 38. ↵ Lukas , D. & Clutton-Brock , T. Monotocy and the evolution of plural breeding in mammals . Behav. Ecol . 31 , 943 – 949 ( 2020 ). OpenUrl CrossRef PubMed 39. ↵ Kaplan , H. , Hill , J. , Lancaster , J. & Hurtado , A. M. A theory of human life history evolution: diet, intelligence, and longevity . Evol. Anthropol . 9 , 156 – 185 ( 2000 ). OpenUrl CrossRef Web of Science 40. ↵ González-Forero , M. & Gardner , A. Inference of ecological and social drivers of human brain-size evolution . Nature 557 , 554 – 557 ( 2018 ). OpenUrl CrossRef PubMed 41. ↵ Cockburn , A. Prevalence of different modes of parental care in birds . Proc. R. Soc. B Biol. Sci . 273 , 1375 – 1383 ( 2006 ). OpenUrl CrossRef PubMed Web of Science 42. ↵ Brouwer , L. & Griffith , S. C. Extra-pair paternity in birds . Mol. Ecol . 28 , 4864 – 4882 ( 2019 ). OpenUrl CrossRef 43. ↵ Low , B. S. Measures of Polygyny in Humans . Curr. Anthropol . 29 , 189 – 194 ( 1988 ). OpenUrl CrossRef Web of Science 44. ↵ Wilson , C. , Oeppen , J. & Pardoe , M. What Is Natural Fertility? The Modelling of a Concept . Popul. Index 54 , 4 ( 1988 ). OpenUrl PubMed 45. ↵ Colleran , H. The cultural evolution of fertility decline . Philos. Trans. R. Soc. B Biol. Sci . 371 , 20150152 ( 2016 ). OpenUrl CrossRef PubMed 46. ↵ Barsbai , T. , Lukas , D. & Pondorfer , A. Local convergence of behavior across species . Science 371 , 292 – 295 ( 2021 ). OpenUrl Abstract / FREE Full Text 47. ↵ Ross , C. T. et al. Greater wealth inequality, less polygyny: rethinking the polygyny threshold model . J. R. Soc. Interface 15 , 20180035 ( 2018 ). OpenUrl CrossRef PubMed 48. ↵ Dyble , M. , Gardner , A. , Vinicius , L. & Migliano , A. B. Inclusive fitness for in-laws . Biol. Lett . 14 , 20180515 ( 2018 ). OpenUrl CrossRef PubMed 49. ↵ Henrich , J. The Secret of Our Success: How Culture Is Driving Human Evolution, Domesticating Our Species, and Making Us Smarter . ( Princeton University Press , Princeton Oxford , 2016 ). doi: 10.1515/9781400873296 . OpenUrl CrossRef 50. ↵ Blöcher , J. et al. Descent, marriage, and residence practices of a 3,800-year-old pastoral community in Central Eurasia . Proc. Natl. Acad. Sci . 120 , e2303574120 ( 2023 ). OpenUrl CrossRef PubMed 51. ↵ Gnecchi-Ruscone , G. A. et al. Network of large pedigrees reveals social practices of Avar communities . Nature 629 , 376 – 383 ( 2024 ). OpenUrl CrossRef PubMed 52. ↵ Penske , S. et al. Kinship practices at the early bronze age site of Leubingen in Central Germany . Sci. Rep . 14 , 3871 ( 2024 ). OpenUrl 53. ↵ Walker , R. S. et al. Living with Kin in Lowland Horticultural Societies . Curr. Anthropol . 54 , 96 – 103 ( 2013 ). OpenUrl CrossRef Web of Science 54. ↵ Kirby , K. R. et al. D-PLACE: A Global Database of Cultural, Linguistic and Environmental Diversity . PLOS ONE 11 , e0158391 ( 2016 ). OpenUrl CrossRef PubMed 55. ↵ Page , A. E. et al. Women’s subsistence strategies predict fertility across cultures, but context matters . Proc. Natl. Acad. Sci . 121 , e2318181121 ( 2024 ). OpenUrl 56. ↵ R Core Team . R: A Language and Environment for Statistical Computisng . ( 2018 ). View the discussion thread. Back to top Previous Next Posted August 23, 2025. 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