He worked tirelessly on publications on shells, birds, ecology and zoogeography. It was the organ of the "Zoogeography and Evolution of Pacific Insects" program. Ouellet published numerous researches on zoogeography, ecology, and behavior. His master's thesis focused on zoogeography of Peruvian bats. In geography zoogeography exists today as the vibrant subfield of biogeography. Zoogeography is the branch that studies distribution of animals. His main subject of research was herpetology and zoogeography of Latin America, especially Ecuador. Over the 19th century, botanical geography and zoogeography combined to form the basis of biogeography.