The goal of this research is to determine the ways that the mechanical properties of foods affect growth and development in primates. This research helps determine why developmental periods differ in primates, and it provides important insights into human developmental prolongation. Through an entire annual cycle, the PIs will investigate how mantled howler monkeys (Alouatta palliata) inhabiting La Isla de Ometepe, Nicaragua develop dietary patterns and foraging behaviors. This research tests hypotheses predicting that both resource toughness (a material's resistance to crack propagation) and behavioral factors (including social dominance and the development of foraging skill) narrow the range of foods that juveniles can eat in comparison to adults. Quantifying the toughness of resources consumed by adults and juveniles will determine whether or not age-based differences in dietary toughness exist. Data collected on the feeding and social behaviors of all howler age/sex classes will indicate the degree to which juveniles suffer dietary deficiencies because of either social exclusion or reduced foraging skill, or both.
The intellectual merit of this project is its application of materials engineering concepts to understanding the biology of development. Previous studies demonstrate that food toughness is a major factor determining primate resource consumption; however, these studies have focused only on adults. The present research adds a growth component to studies relating resource toughness and primate feeding behaviors. Investigations of juvenile diet are crucial because foraging behaviors and diets of young primates appear to correlate strongly with population growth rates. The present research investigates juvenile diet in order to explain the relationships among life history strategies, demographic patterns, and dietary mechanical properties.
The broader impacts of this project include its clarification of the factors that influence juvenile diets. Because the diet consumed during juvenility has consequences for adulthood, this research has direct applications to developing animal models to assess nutritional requirements. The relatively short lifespan of howler monkeys relative to humans means that the long term effects of early life feeding success, if any, on adulthood can ultimately be assessed. Additionally, this investigation identifies the resources crucial to mantled howler growth and development and can be used to implement successful conservation and biodiversity programs. In order to achieve these goals, this study involves collaboration with Nicaraguan scientists. Collaborating with these scientists enables the expansion of biological research in a critical, yet understudied, area of the world.
