Xiaojie Tian, Tetsuhiro Kidokoro, Francis Mundia Mwangi, Elijah Gitonga Rintaugu
{"title":"Childhood Physical Activity and Developmental Niche in Contemporary Pastoralist Maasai Community in Southern Kenya","authors":"Xiaojie Tian, Tetsuhiro Kidokoro, Francis Mundia Mwangi, Elijah Gitonga Rintaugu","doi":"10.1002/ajpa.70283","DOIUrl":"10.1002/ajpa.70283","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>Although increasing attention has been directed toward childhood physical activity (PA) in small-scale societies of the Global South, evidence across the full developmental span remains limited and is often interpreted without sufficient attention to local parental environments, norms, or children's social roles. This study examines PA among pastoralist Maasai children in southern Kenya from an ecocultural perspective.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Materials and Methods</h3>\u0000 \u0000 <p>PA and sedentary behavior were assessed in 180 children aged 2–18 years using waist-worn three-axis accelerometers, which enabled comparisons across age, sex, day type, and school attendance. Quantitative data were complemented by long-term ethnographic fieldwork on children's daily routines and parental practices, providing context for the developmental niche.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Maasai children demonstrated consistently high levels of moderate-to-vigorous physical activity (MVPA) across all ages. Mean MVPA rose from 89 min/day (ages 2–5) to 130–143 min/day (ages 6–12), accompanied by 17,000–21,000 steps/day. Boys were generally more active than girls. Variation by school attendance reflected local norms emphasizing childhood autonomy, staged social participation, and engagement with the landscape through daily tasks and play.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Discussion</h3>\u0000 \u0000 <p>These findings provide the first comprehensive assessment of childhood PA across the full developmental span of a pastoralist Maasai community. Children's high activity levels are sustained within culturally meaningful developmental niches that foster autonomy and embodied engagement with the land, alongside contemporary transitions such as schooling. The study underscores the importance of etic–emic integration for understanding childhood PA in small-scale societies.</p>\u0000 </section>\u0000 </div>","PeriodicalId":29759,"journal":{"name":"American Journal of Biological Anthropology","volume":"190 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajpa.70283","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148144835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zitan Song, Sandra A. Heldstab, Richard F. Kay, E. Christopher Kirk, Carel P. van Schaik
{"title":"Sensorimotor Complexity and Cognition as Predictors of Primate Brain Size","authors":"Zitan Song, Sandra A. Heldstab, Richard F. Kay, E. Christopher Kirk, Carel P. van Schaik","doi":"10.1002/ajpa.70281","DOIUrl":"https://doi.org/10.1002/ajpa.70281","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>As animal brain size increases, cognitive performance generally increases. However, other key brain functions, such as the regulation of somatic processes, processing of sensory input, and planning and initiation of motor actions, are also closely tied to brain size. Thus, the observed correlations between cognitive performance and brain size may be spurious, a suggestion boosted by recent work showing fishes perform as well as primates on various cognitive tests.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Materials and Methods</h3>\u0000 \u0000 <p>Here, we applied multi-response Bayesian phylogenetic mixed models, in which the four main functions of brains were dependent variables predicted by brain size as the independent variable, as well as a phylogenetic path analysis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Among varying sets of primate species, brain size strongly predicted somatic functions (as indexed by body size), with similar, somewhat weaker effect sizes for the other three functional traits. The path analysis suggested that body size also independently affected brain size, which in turn predicted the three non-somatic functions with nearly equal strength.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Discussion</h3>\u0000 \u0000 <p>This result suggests that the correlation between body and brain size is the sum of two distinct processes: correlated evolution between body and brain size and a brain size effect on somatic functions, although estimating the strength of the two components is currently impossible. We reject the challenge posed by cognition data on fishes, but find that primate cognition tightly coevolved with sensory and motor functions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":29759,"journal":{"name":"American Journal of Biological Anthropology","volume":"190 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajpa.70281","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148099335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yifei Fan, Shiwu Ma, Qiyu Yin, Jun Yan, Jiajie Zhao, Shenwen Pang, Xueping Ji, Miguel Delgado, Pianpian Wei
{"title":"A Reappraisal of the Frontal Bone and Mandibles of Late Pleistocene Hominins From Maludong, Southwestern China: A 3D Geometric Morphometric Perspective","authors":"Yifei Fan, Shiwu Ma, Qiyu Yin, Jun Yan, Jiajie Zhao, Shenwen Pang, Xueping Ji, Miguel Delgado, Pianpian Wei","doi":"10.1002/ajpa.70287","DOIUrl":"10.1002/ajpa.70287","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>Multiple Late Pleistocene hominin fossils have been discovered at Maludong, southwestern China, which exhibit a mosaic of archaic and modern human traits, revealing high hominin diversity. To further investigate the regional variation of hominins during the Late Pleistocene in East Asia, this study presents a 3D geometric morphometric analysis of the Maludong frontal bone and mandibles.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>CT-scanned 3D models of Maludong frontal bone (MLDG 1704) and mandibular (MLDG 1679/1706) fossils were analyzed using 3D geometric morphometrics, alongside comparative 3D models of Pleistocene hominins and fossil/extant modern humans.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The Maludong frontal bone and mandibular shape variation (MLDG 1706) fall within the range of variation observed in Late Pleistocene <i>Homo sapiens</i> and modern humans, exhibiting distinct modern human-like traits. Specifically, the frontal bone shows a reduced supraorbital ridge and a broad, globular frontal squama with greater curvature. The mandible displays a more vertical symphysis and a more elongated ramus. However, the MLDG 1679 mandible falls within the morphological range of Late Pleistocene <i>Homo sapiens</i> and Neanderthals, characterized by a shorter and more robust ramus.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Discussion</h3>\u0000 \u0000 <p>These findings indicate that the Maludong hominins share biological affinity with <i>Homo sapiens</i>, potentially reflecting broader evolutionary trends in modern human morphology. Meanwhile, the robusticity observed in these and other Late Pleistocene East Asian fossils highlights the wide regional craniomandibular diversity of East Asian hominins during the Late Pleistocene. This study thereby contributes to a more comprehensive understanding of the morphological diversification and the complex evolutionary history of Late Pleistocene hominins in East Asia.</p>\u0000 </section>\u0000 </div>","PeriodicalId":29759,"journal":{"name":"American Journal of Biological Anthropology","volume":"190 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148044052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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