Sorex Cinereus, commonly known as the masked shrew, is a small mammal found in North America. Other synonyms for this species include the cinereus shrew, common shrew, and gray shrew. The masked shrew is typically found in forested areas and is known for its fast metabolism and constant need for food. These small, agile creatures are an important part of the food chain, eating insects, snails, and other small invertebrates, while also serving as prey for larger mammals. Despite their diminutive size, the masked shrew plays a significant role in maintaining the ecological balance of their habitat.