Sciurus stramineus Eydoux and Souleyet, 1841, is a large-bodied squirrel commonly called the Guayaquil squirrel. S. stramineus is characterized by a distinct grizzled-gray pelage with dark feet and ears, a long tail, and a distinctive white “collar” behind the ears. It is native to the western slope of the Andes, occurring from dry or humid tropical forests at sea level to high-elevation montane forests up to 2,000 m in Ecuador and Peru. S. stramineus is adaptable, adjusting to anthropogenic changes and living close to human settlements, in coffee plantations, with an introduced population in Lima, Peru. Because of a tolerance for living in proximity to humans, S. stramineus is also a concern for transmission of diseases such as leptospirosis and Chagas disease.