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Sources of variation in weaned age among wild chimpanzees in Gombe National Park, Tanzania.

Publication ,  Journal Article
Lonsdorf, EV; Stanton, MA; Pusey, AE; Murray, CM
Published in: American journal of physical anthropology
March 2020

A key feature of human life history evolution is that modern humans wean their infants 2-4 years earlier on average than African apes. However, our understanding of weaning variation in apes remains limited. Here we provide the first such report in chimpanzees by examining weaned age variation using long-term data from Gombe National Park, Tanzania.We analyzed 41 years of observational behavioral data from 65 offspring of 29 mothers to examine the relationships between weaned age (defined as cessation of suckling) in wild chimpanzees and maternal age, dominance rank and parity, and offspring sex. We used Cox proportional hazards regression with mixed effects to model time to weaning and to examine potential sources of variation in offspring weaned age.We found that male offspring were less likely than female offspring to wean by a given age and that weaned age of males varied more than weaned age of females. In addition, maternal dominance rank interacted with offspring age, such that low-ranking mothers were less likely to wean offspring early, but this effect decreased with offspring age.We found that male offspring and offspring of low-ranking females were less likely to wean early, but did not find evidence for variable weaning according to maternal age or parity. As more data accumulate, we will be better able to disentangle the effects of maternal dominance rank, age and parity. Such studies will not only provide a richer understanding of living ape life history characteristics, but will also provide an important framework for understanding the evolution of early weaning in humans.

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Published In

American journal of physical anthropology

DOI

EISSN

1096-8644

ISSN

0002-9483

Publication Date

March 2020

Volume

171

Issue

3

Start / End Page

419 / 429

Related Subject Headings

  • Weaning
  • Tanzania
  • Social Dominance
  • Parks, Recreational
  • Pan troglodytes
  • Models, Biological
  • Male
  • Female
  • Anthropology
  • Animals
 

Citation

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Lonsdorf, E. V., Stanton, M. A., Pusey, A. E., & Murray, C. M. (2020). Sources of variation in weaned age among wild chimpanzees in Gombe National Park, Tanzania. American Journal of Physical Anthropology, 171(3), 419–429. https://doi.org/10.1002/ajpa.23986
Lonsdorf, Elizabeth V., Margaret A. Stanton, Anne E. Pusey, and Carson M. Murray. “Sources of variation in weaned age among wild chimpanzees in Gombe National Park, Tanzania.American Journal of Physical Anthropology 171, no. 3 (March 2020): 419–29. https://doi.org/10.1002/ajpa.23986.
Lonsdorf EV, Stanton MA, Pusey AE, Murray CM. Sources of variation in weaned age among wild chimpanzees in Gombe National Park, Tanzania. American journal of physical anthropology. 2020 Mar;171(3):419–29.
Lonsdorf, Elizabeth V., et al. “Sources of variation in weaned age among wild chimpanzees in Gombe National Park, Tanzania.American Journal of Physical Anthropology, vol. 171, no. 3, Mar. 2020, pp. 419–29. Epmc, doi:10.1002/ajpa.23986.
Lonsdorf EV, Stanton MA, Pusey AE, Murray CM. Sources of variation in weaned age among wild chimpanzees in Gombe National Park, Tanzania. American journal of physical anthropology. 2020 Mar;171(3):419–429.
Journal cover image

Published In

American journal of physical anthropology

DOI

EISSN

1096-8644

ISSN

0002-9483

Publication Date

March 2020

Volume

171

Issue

3

Start / End Page

419 / 429

Related Subject Headings

  • Weaning
  • Tanzania
  • Social Dominance
  • Parks, Recreational
  • Pan troglodytes
  • Models, Biological
  • Male
  • Female
  • Anthropology
  • Animals