Brazilian graduate student Gisele Ferreira reaches for a specimen of Cane Toad (Rhinella marina) found on the western side of Marajó, during an excursion with a team of researchers from Cal Poly Humboldt on Marajó Island. (Photo courtesy Pedro Peloso)

Marajó is the world's largest river island. It is about the size of the state of West Virginia and located in Brazil at the intersection of the Amazon River and Atlantic Ocean. Researchers from Cal Poly Humboldt have initiated a new research project on the island to learn more about a long-overlooked story of biodiversity and evolution.

Joining the Exchange to discuss the project is Cal Poly Humboldt Associate Professor, Silvia Pavan, PhD.

The project is led by Cal Poly Humboldt Zoology Professors Silvia Pavan and Pedro Peloso, and Angelo State University Biology Professor Edson Abreu, in collaboration with researchers and students from across the U.S. and Brazil. The team is exploring how and when different species reached the island—and whether they’ve evolved to fit Marajó’s distinct environments.

There are two different types of landscapes on Marajó. Its western side is covered in rainforest, while open grasslands dominate the east.