Publication Date

2021

Abstract

The purpose of this dissertation is to measure and explain age- and sex-related differences in energy expenditure, physical activity, and patterns of horticultural work, in the Tsimane’, a subsistence forager-horticulturalist population from the Bolivian Amazon. Changes in the way energy is used with advancing age has important implications for the tradeoffs negotiated within the aging body as it partitions increasingly limited energy among competing life functions. It is guided by a theoretical framework which posits the co-evolution of the unique suite of fast and slow human life history traits, cooperative production of resources, and ageand sex-specific schedules of growth, production, and aging. It is composed of three interrelated studies. Firstly, I used the doubly-labeled water method to estimate total energy expenditure (TEE) in forty Tsimane’ men and women. Secondly, I compared age-related differences in adult physical activity between men and women, and between the Tsimane’ and the United States. Thirdly, I examined variation in horticultural work effort using a survey methodology. The results indicate that being greater than 60 years of age is associated reduced TEE and that being male is associated with increased TEE. Age-related differences in physical activity are greater for the more active Tsimane’ relative to the US and men relative women. However, these age-related differences are proportionally similar. Finally, men and women become more similar in their annual work effort and field size. However, women provide substantial help in their spouses fields especially during peak child dependency. Men increase their work effort when more dependent children are present. While early in life we may expect ecological and sex-specific differences to determine much of the variation in energy expenditure, physical activity, and subsistence effort, the biological consequences of aging by-in-large swamp the effect of variation in ecological environment and sex as old age approaches. Lastly, age-related changes to horticultural work reflect a life history strategy of cooperative production of resources, childcare, and provisioning between men and women.

Document Type

Dissertation

Language

English

Degree Name

Evolutionary Anthropology

Level of Degree

Doctoral

Department Name

Anthropology

First Committee Member (Chair)

Martin Muller

Second Committee Member

Hillard Kaplan

Third Committee Member

Michael Gurven

Fourth Committee Member

Siobhán Mattison

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