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Abstract ObjectivesThe prolonged juvenile period exhibited by primates is an evolutionary conundrum. Here we examine wild chimpanzee feeding development in the context of two hypotheses regarding prolonged development in primates: the needing‐to‐learn hypothesis and the expensive brain hypothesis. Material and MethodsWe studied wild chimpanzee (Pan troglodytes schweinfurthii) offspring at Gombe National Park, Tanzania. We analyzed 41 years of observational behavioral data collected between 1975 and 2016 from 81 offspring. We characterized feeding development in the first 10 years of life via four different measures: (1) proportion of observation time spent feeding; (2) diet composition; (3) diet breadth; and (4) diet maturity as measured by similarity to maternal diet. We used mixed effects models to examine changes with age and by sex, while controlling for season. ResultsFeeding time, diet breadth, and diet maturity exhibited the most substantial increases with age in the first 6 years, with no significant change thereafter. Males and females showed different patterns of change in diet breadth by age, but did not differ by age 10. Diet composition did not change significantly with age and did not differ by sex. DiscussionWe found that chimpanzee offspring attained adult‐like feeding behaviors between 4 and 6 years of age, concomitant with the completion of weaning. Thus, our data do not support the needing‐to‐learn feeding skills hypothesis of a prolonged juvenile period, but additional data are needed to evaluate how and when adolescent chimpanzees are able to make foraging decisions independent of their mothers. Existing data on growth provides support for the expensive brain hypothesis, however, these hypotheses are not necessarily mutually exclusive. As more studies across taxa accumulate sufficient datasets on a range of developmental metrics, we will be able to achieve a more robust understanding of prolonged development in primates.
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Biocultural Determinants of Mothers' Complementary Feeding Decisions in the Urban Brazilian Amazon
ABSTRACT ObjectiveComplementary feeding (CF) occurs during a critical period of infant growth and development with life‐long health implications. Despite international efforts, there remains significant variation in the adequacy of complementary diets across settings. In Brazil, there is marked variation in adherence to CF guidelines and infant growth outcomes, with the north (Amazon) lagging other regions of the country. This study aimed to characterize the complementary diet and develop a model to explain feeding decisions in the Amazonian city of Belém. MethodsWith a sample ofn = 30 mothers, we combined 24‐h dietary recalls, a pile‐sorting activity, and in‐depth interviews to address study aims. Using descriptive statistics, we analyzed the pile‐sort data to characterize the evolving complementary diet. Then, using thematic analysis of interview transcripts, we identified the most salient factors shaping mothers' feeding decisions. ResultsWhile there was variation in opinion regarding the timing of introduction of liquids other than breastmilk and ultra‐processed convenience foods, we found high consensus regarding the ideal complementary diet which, beginning at 6 months, met WHO dietary diversity guidelines and evolved with infant age. Three themes—integrating and applying trusted sources of advice, infant readiness and future health, and challenges to feeding ideals—illustrate how socioeconomic, cultural, and infant bio‐behavioral cues interact to shape CF. ConclusionEfforts to improve infant feeding must move beyond identifying individual factors and toward biocultural models that consider how political–economic and local contexts interact to influence the ethnomedical systems, household sociocultural dynamics, including income, gender, and age‐based responsibilities, and power relations that shape feeding behaviors.
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- Award ID(s):
- 1921592
- PAR ID:
- 10592764
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- American Journal of Human Biology
- Volume:
- 37
- Issue:
- 5
- ISSN:
- 1042-0533
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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