James Hayward (Biology), Shandelle Henson (Mathematics)
Using mathematical models to predict haulout patterns of marine iguanas
Marine iguanas, a species endemic to the Galapagos Islands, spend most of their time "hauled out" on land but feed exclusively in the sea. We propose using mathematical models to describe, explain, and predict haulout behavior in these animals. The tendency to haul out in large aggregations makes marine iguanas behaviorally analogous to the marine birds and mammals which we have studied previously; marine iguanas differ, however, in that they are reptiles. A study of a reptilian group will allow us to extend our successful interdisciplinary methodology to another major taxonomic group. Accurate predictions of behavioral dynamics require the construction of compartmental mathematical models that operate on scales at which deterministic trends emerge from individual variability. Tide height, time of day, air temperature, and other environmental variables are known to impact patterns of haulout in marine iguanas, but no previous study has incorporated these variables into a single integrated model. Integrating a suite of variables such as these into a single model is better suited to mathematical than to statistical techniques and will be more likely to provide a nuanced model for the behavior of this species. The modeling methodology (1) tests the null hypothesis that temporal haulout patterns of marine iguanas are independent of tide level, solar elevation, air temperature, and body size, and (2) tests a suite of alternative hypotheses that include these factors. Funds will be used for faculty and graduate student travel to the Galapagos Islands, local Galapagos transportation, a study permit, lodging, equipment, and supplies.