Skip to content
DraconiticResearch
Search Sources API
210,089 studies31 sourcesUpdated 48 min ago
Peer-reviewedCC BYNature Ecology & Evolution

Comparative primate analysis shows that humans are not unique in having a tight cephalopelvic fit at birth

  • Nicole Torres‐Tamayo1,2,3
  • Stefan Schlager4
  • Eishi Hirasaki5
  • Timothy D. Smith6
  • Todd C. Rae7
  • Lia Betti8
8 affiliations
  1. 1Department of Anthropology, University College London, London, UK. [email protected]
  2. 2Hominin Origins Research Group, Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Cerdanyola del Vallés, Spain. [email protected]
  3. 3Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland. [email protected]
  4. 4Department of Oral and Maxillofacial Surgery, University Medical Center Freiburg, Freiburg im Breisgau, Germany
  5. 5Institute for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Japan
  6. 6Department of Health and Rehabilitation Sciences, Program of Physical Therapy, Slippery Rock University, Slippery Rock, PA, USA
  7. 7Department of Ecology and Evolution, School of Life Sciences, University of Sussex, Falmer, UK
  8. 8Department of Anthropology, University College London, London, UK. [email protected]
Open at sourcePDFDOICite

Abstract

Human childbirth is regarded as uniquely difficult among primates, due to a tight cephalopelvic fit thought to result from an evolutionary trade-off between adaptations to bipedal locomotion and increasing brain size. This impression, however, may be an artefact of past adoption of anthropocentric measurements that underestimate birth challenges in non-human primates. Here we re-evaluate cephalopelvic proportions using species-specific three-dimensional data of the pelvic inlet along with neonatal cranial dimensions from a broad sample of extant primates. Results reveal that maternal body size is a key factor to consider. A tight cephalopelvic fit occurs in species with proportionately larger neonates, smaller pelves or a combination of both. The latter is the case in humans, producing the tightest fit among extant apes, but a similar combination of factors explains much more extreme cephalopelvic proportions in other species. Our findings reveal a diversity of obstetrical dilemmas across primates.

Related

  1. Comparative functional genomics of six Pectobacterium species reveals core and unique fitness determinants in potato tubers
    T. C. Helmann, M. A. Karp, M. L. Daughtrey +3
    bioRxivPreprintCC0Full textMicrobiologybioRxiv
  2. Comparative analysis of myeloperoxidase deficiency in humans and mice: Conserved and species-specific effects on neutrophil biology
    Maysam Ahdab, Henning Guthoff, Nathalie Nix +20
    Redox BiologyPeer-reviewedCC BYFull textImmunologyDOAJ
  3. Modulation and Integration in a local processor having input from two distinct sources
    Jim W. Kay, Bruce P. Graham
    arXivPreprintCC BY-NC-ND 4.0Full textNeurosciencearXiv
  4. Aerobic preference in the marine protist Paradiplonema papillatum having anaerobic genomic potential
    Barbora Bučková, Kristína Záhonová, Zuzana Dzureková +13
    BMC BiologyPeer-reviewedCC BY 4.0Molecular biology & gene regulationGeneral biologyCrossref
  5. Silver spoon effect: early-life environment and adult survival in a primate.
    Martine Perret, Aude Anzeraey, Fabienne Aujard
    HALPreprintPublisher termsFull textGeneral biologyPhysiologyHALbioRxiv

Cite

BibTeXRIS
BibTeX
@article{torrestamayo2026comparative,
  title = {{Comparative primate analysis shows that humans are not unique in having a tight cephalopelvic fit at birth}},
  author = {Nicole Torres‐Tamayo and Stefan Schlager and Eishi Hirasaki and Timothy D. Smith and Todd C. Rae and Lia Betti},
  journal = {Nature Ecology \& Evolution},
  year = {2026},
  month = jun,
  doi = {10.1038/s41559-026-03102-5},
  url = {https://doi.org/10.1038/s41559-026-03102-5},
  note = {CC BY},
}
RIS
TY  - JOUR
TI  - Comparative primate analysis shows that humans are not unique in having a tight cephalopelvic fit at birth
AU  - Nicole Torres‐Tamayo
AU  - Stefan Schlager
AU  - Eishi Hirasaki
AU  - Timothy D. Smith
AU  - Todd C. Rae
AU  - Lia Betti
PY  - 2026
DA  - 2026/06/29
JO  - Nature Ecology & Evolution
DO  - 10.1038/s41559-026-03102-5
UR  - https://doi.org/10.1038/s41559-026-03102-5
AB  - Human childbirth is regarded as uniquely difficult among primates, due to a tight cephalopelvic fit thought to result from an evolutionary trade-off between adaptations to bipedal locomotion and increasing brain size. This impression, however, may be an artefact of past adoption of anthropocentric measurements that underestimate birth challenges in non-human primates. Here we re-evaluate cephalopelvic proportions using species-specific three-dimensional data of the pelvic inlet along with neonatal cranial dimensions from a broad sample of extant primates. Results reveal that maternal body size is a key factor to consider. A tight cephalopelvic fit occurs in species with proportionately larger neonates, smaller pelves or a combination of both. The latter is the case in humans, producing the tightest fit among extant apes, but a similar combination of factors explains much more extreme cephalopelvic proportions in other species. Our findings reveal a diversity of obstetrical dilemmas across primates.
SN  - 2397-334X
ER  -