As a diverse mammalian clade defined by encephalization and an increased reliance on learned behaviors, primates serve as a uniquely well-suited subject for the study of how environmental factors may influence the diversity of brain morphology. Endocasts, which are 3D models of the cranial cavity, have been proven to be reliable proxies for brain shape and size and provide an accessible method for studying brain morphology. While it has been demonstrated that environment has caused convergent cranial morphology in lemur species, more investigation is necessary to uncover the exact causal variables of these changes and how they affect primates more broadly. In this study, we test the hypothesis that climatic factors contribute to morphological differences in the neocortex, olfactory bulbs, and cerebellum among primate species. For example, food scarcity caused by greater variability in rainfall and temperature may be correlated with investment in regions associated with learning and processing as described by the cognitive buffer hypothesis. Thus, we predict that increased rainfall leads to increased food availability and an increase in neocortex size which is responsible for higher order functions. To test our hypothesis, we obtained CT scans of primate skulls from the Natural History Museum, London, United Kingdom. We then used 3D Slicer to create endocasts from the cranial cavity and quantify endocranial morphology using landmark-based geometric morphometrics. We used phylogenetic comparative methods in R to test whether climate variables like temperature, rainfall, and altitude have induced changes in endocast morphology across species. Our findings will enhance the understanding of the evolutionary mechanisms particular to our own lineage and may help us better predict how Anthropogenic changes to climate will affect the evolution of organisms moving forward.

Every spring, a small population of less than 20 gray whales (Eschrichtius robustus), referred to as “Sounders,” migrate to northern Puget Sound (NPS), Washington State. They stay in this region for two to three months, often leaving before June, to continue their migration to Alaska. In contrast to gray whales in other locations, NPS gray whales primarily forage on ghost shrimp (Callianassa californiensis). These small crustations live in the sediment in the intertidal to shallow subtidal zones, so gray whales must wait for higher tides to feed. Although there have been recurring studies of NPS gray whales since 1990, sighting data have not been analyzed for spatiotemporal trends, apart from a few select years. The purpose of this research is to identify how NPS gray whales are distributed within the NPS throughout the foraging season and between years. I used ArcGIS to analyze sightings data collected by Cascadia Research Collective from 1990 to 2023 for spatial and temporal trends. In NPS, gray whale abundance and time spent in the region have been increasing, especially during gray whale unusual mortality events which are likely caused by reduced prey abundance due to environmental anomalies and decreased upwelling. I hypothesized that increases in the population widened their distribution in the region to accommodate for more individuals. Implications of this research include a better understanding of the areas that may be more frequented by Sounders, which could help decrease negative interactions between marine vessels and whales. In addition, these areas could indicate places for further research to better understand increased gray whale presence on the ecosystem as a whole. Future research may also include the distribution and habitat preference of individual whales, and associations between certain whales.