Nicholas Blurton-Jones

University of California, Los Angeles | UCLA · Department of Anthropology

Human evolutionary demography is an emerging field blending natural science with social science. This edited volume provides a much-needed, interdisciplinary introduction to the field and highlights cutting-edge research for interested readers and researchers in demography, the evolutionary behavioural sciences, biology, and related disciplines. By...

Across vertebrates, species with intense male mating competition and high levels of sexual dimorphism in body size generally exhibit dimorphism in age-specific fertility. Compared with females, males show later ages at first reproduction and earlier reproductive senescence because they take longer to attain adult body size and musculature, and main...

The century long publication of this journal overlapped major changes in the sciences it covers. We have been eyewitnesses to vast changes during the final third of the last century and beginning of this one, momentous enough to fundamentally alter our work separately and collectively. One (NBJ) from animal ethology, another from western North Amer...

The Hadza, an ethnic group indigenous to northern Tanzania, are one of the few remaining hunter-gatherer populations. Archaeology shows 130,000 years of hunting and gathering in their land but Hadza are rapidly losing areas vital to their way of life. This book offers a unique opportunity to capture a disappearing lifestyle. Blurton Jones interweav...

Unlike other primate males, men invest substantial effort in producing food that is consumed by others. The Hunting Hypothesis proposes this pattern evolved in early Homo when ancestral mothers began relying on their mates' hunting to provision dependent offspring. Evidence for this idea comes from hunter-gatherer ethnography, but data we collected...

Archaeological data are frequently cited in support of the idea that big game hunting drove the evolution of early Homo, mainly through its role in offspring provisioning. This argument has been disputed on two grounds: (1) ethnographic observations on modern foragers show that although hunting may contribute a large fraction of the overall diet, i...

Humans have a much longer juvenile period (weaning to first reproduction, 14 or more years) than their closest relatives (chimpanzees, 8 years). Three explanations are prominent in the literature. (a) Humans need the extra time to learn their complex subsistence techniques. (b) Among mammals, since length of the juvenile period bears a constant rel...

Female postreproductive life is a striking feature of human life history and there have been several recent attempts to account for its evolution. But archaeologists estimate that in the past, few individuals lived many postreproductive years. Is postreproductive life a phenotypic outcome of modern conditions, needing no evolutionary account? This...

Humans have a much longer juvenile period (weaning to first reproduction, 14 or more years) than their closest relatives (chimpanzees, 8 years). Three explanations are prominent in the literature. (a) Humans need the extra time to learn their complex subsistence techniques. (b) Among mammals, since length of the juvenile period bears a constant rel...

Hadza huntergatherers display economic and social features usually assumed to indicate the dependence of wives and children on provisioning husbands and fathers. The wives and children of better Hadza hunters have been found to be betternourished, consistent with the assumption that men hunt to provision their families. Yet, as is common among fora...

In most human foraging societies, the meat of large animals is widely shared. Many assume that people follow this practice because it helps to reduce the risk inherent in big game hunting. In principle, a hunter can offset the chance of many hungry days by exchanging some of the meat earned from a successful strike for shares in future kills made b...

Comparative studies have become both more frequent and more important as a means for understanding the biology, behaviour and evolution of mammals. Primates have complex social relationships and diverse ecologies, and represent a large species radiation. This book draws together a wide range of experts from fields as diverse as reproductive biology...

Despite recent, compelling challenge, the evolution of Homo erectus is still commonly attributed to big game hunting and/or scavenging and family provisioning by men. Here we use a version of the "grandmother" hypothesis to develop an alternative scenario, that climate-driven adjustments in female foraging and food sharing practices, possibly invol...

Long postmenopausal lifespans distinguish humans from all other primates. This pattern may have evolved with mother-child food sharing, a practice that allowed aging females to enhance their daughters' fertility, thereby increasing selection against senescence. Combined with Charnov's dimensionless assembly rules for mammalian life histories, this...

Reproductive experiences for women in today's affluent Western nations differ from those of women in hunting and gathering societies, who continue the ancestral human pattern. These differences parallel commonly accepted reproductive risk factors for cancers of the breast, endometrium and ovary. Nutritional practices, exercise requirements, and bod...

Children of the hunting and gathering !Kung San seldom foraged, especially during the long dry season. In contrast, children of Hadza foragers in Tanzania often forage, in both wet and dry seasons. Because we have argued that the economic dependence of !Kung children has important consequences, we must try to understand why they did not forage. Exp...

This is a report on the demography of the Hadza, a population of East African hunter-gatherers. In it, we describe the results of a census, and our estimation of age structure, survivorship, mean age of women at childbearing, number of live children, total population size and density, and rate of change since 1967. We show that relevant measures fi...

Large mammal kill sites created by Hadza hunter-gatherers are described and analysed. Three important observations result. First, Hadza kill sites are likely to contain disproportionate numbers of very large-bodied prey (live weight > 200 kg). Smaller animals are taken far more often, but will be underrepresented in kill site assemblages because of...

The assumption that large mammal hunting and scavenging are economically advantageous to hominid foragers is examined in the light of data collected among the Hadza of northern Tanzania. Hadza hunters disregard small prey in favour of larger forms (mean adult mass greater than or equal to 40 kg). Here we report experimental data showing that hunter...

Recent research on prehistoric hunter-gatherer site structure continues to be concerned primarily with the identification of discrete, activity-specific areas within sites (e.g., Carr 1984; Hietala 1984; Flannery 1986). However, an increasingly large body of ethnoarchaeological data suggests that such areas may be rare in the archaeological record,...

Far from being involved in a fundamental division, the study of evolution and human behavior is fortunate to have three potentially productive paradigms which could usefully coexist. In so far as “Darwinian psychology” (DP) is the study of causal mechanisms, guided by thinking about the tasks the mechanisms must perform, it has a clear place alongs...

Data on 54 cases of large mammal body part transport among the Hadza are reanalysed. Results are consistent with those previously reported. Within species, parts are ranked on a uni-dimensional scale for transport: high ranked parts are more likely to be moved from kill sites to base camps, low ranked parts less likely. For most species in the samp...

A study of Hadza hunting and scavenging practices, patterns of medium/large mammal carcass dismemberment and transport from kill sites to base camps, and subsequent processing and disposal of bones reveals archaeological bone assemblage formation processes among these hunter-gatherers in northern Tanzania. Body part transport patterns are highly va...

In industrial societies around 20% of children aged 1 to 3 years wake at night and cry enough to wake their parents. We suggest that instead of regarding this common behavior as pathological we might consider whether it is, or could once have been, an adaptive response. We suggest that one outcome of this behavior, plausibly adaptive, would be dela...

Blurton Jones and Sibly (1978) developed a model of costs (weight of food and baby carried while foraging) of !Kung women's reproduction under ecological-economic constraints that were described by Lee (1972). Predictions are drawn from this model and tested on Howell's (1979) data from reproductive histories of 172 individual women.Women were rate...

Long interbirth intervals (IBIs) are reported by Lee and by Howell for !kung women, averaging around 4 years between births. Is this low rate of births maladaptive? An earlier analysis of the ecological constraints upon !kung women suggested that it might not be. Given the observed features of !kung ecology, shorter IBIs require a mother to carry m...

Winterhalder, Bruce, and Eric Alden Smith, eds. Hunter‐Gatherer Foraging Strategies: Ethnographic and Archaeological Analyses. Chicago: University of Chicago Press, 1982. x + 268 pp. including bibliography and index. $18.00 cloth, $7.50 paper.

First-born children, 34 boys and 25 girls, were observed during separation from their mother and for 5 min after reunion. The separation occurred at the end of a playgroup session of about two hours in which three other M-C pairs and a nursery nurse were also present and could interact freely with the separating and separated child. There was a bas...

Individuals will be selected to fight only for a fitness gain. If food is found in large packages, some of the package falls high on a diminishing returns curve of the fitness value of the food to the finder. It will not pay the finder to defend such portions against a hungry latecomer. If food is found on different occasions by different individua...

A prospective study of primiparous English women and their newborns failed to replicate previous findings that greater irritability was related to higher maternal blood pressure during pregnancy and labour. This apparent lack of replication prompted a search for fetal variables capable of mediating the blood pressure--irritability relationships. Re...

In a longitudinal study in which 59 first-born middle class children were observed in the company of other children of the same age and with their mothers, a high frequency of attacks on other children by children nearly two years old was correlated with absent or delayed response by the mother to the child's crying after falls, etc. Other aspects...

Mean birthweight, even before induced births became commonplace, is slightly lower than the birthweight at which perinatal mortality is lowest. This finding, once hard to explain by natural selection, is shown to be exactly in line with predictions from natural selection theory.Das mittlere Geburtsgewicht ist etwas niedriger als das Geburtsgewicht,...

An association was found in a sample of 59 healthy middle‐class first‐born babies between regular night‐waking at one year old and pre‐ and perinatal events. The findings closely resemble those reported by Bernal (1973). The only measure of parental behaviour discriminating night wakers from regular sleepers was that mothers of wakers responded mor...

Observations are reported from 7 years of breedingM. arctoides in a small caged colony. From a stock of two males and six females 18 offspring have been born and 17 reared despite leaving young with the mother for approximately 2 years and restricted access between sexes. Overt menstrual bleeding is inconspicuous and external signs of oestrus are m...

Data are given for sexual maturation in a male (fertile mating at 3.25 years post-natal) and female (fertile mating at 3.0 years post-natal)M. arctoides. Comparisons with data forM. mulatta andM. fuscata suggest that these ages are unusually early for macaques.

The establishment of a small breeding colony of Macaca arctoides is described and compared with reports on breeding Macaca mulatta. Despite restrictions imposed on the breeding methods by a developmental ethological study, 7 young, 6 of which were conceived in the laboratory, have been obtained from 6 females in just over 3 years.

Discusses various features of the ethological method and illustrates the possible roles of evolutionary theory in the study of the development of social behavior. (6 p ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)

Evolutionary life-history theory and demography provide strong reasons to suppose that long human life spans are not a recent novelty. Here we focus on one robust model of mammalian life history evolution, and a grand- mother hypothesis about our own lineage that is based upon it. This hy- pothesis takes long adult life spans to be an ancient human...

Human life histories differ from those of other animals in several striking ways. Recently Smith and Tompkins (1995, p. 258) highlighted the combination of "slow" and "fast" features of human lives. Our period of juvenile dependency is unusually long, our age at first reproduction is late, and we have the maximum life span of the terrestrial animal...

In this chapter we discuss explanations for the diversity of behavior of contemporary forager populations. Other contributors document variation among southern African savanna Bushman groups, and central African forest Pygmies. We confine ourselves to trying to explain some differences between two savanna groups who have been studied quantitatively...

Facial expressions and gestures seen in eight wild caught adult and three laboratory born stump-tailed macaques are described. Systematic observations, designed to show the association of these with attack, fleeing, grooming, or copulating are reported. The behaviour is in general very similar to that of other macaques. However, we find that Presen...

[Sabine's Gull, Xema sabini is a morphologically aberrant gull, breeding in the Arctic. This paper describes its breeding behaviour, as recorded in the region of Hooper Bay, W. Alaska (61° 35' N, 166° 05' W) in the summer of 1960. The object of this study has been, not just to describe the behaviour, but to try to relate it to the species' ecology,...