A "littleneck" is a type of small clam, specifically known as Mercenaria mercenaria. These clams are popular in seafood dishes due to their sweet flavor and tender texture. Littlenecks are typically harvested from coastal waters and are often served steamed or raw on the half shell. In addition to their culinary uses, littlenecks play an important role in marine ecosystems. They help filter water, contributing to a healthier environment by removing excess nutrients and pollutants. Their presence indicates a balanced ecosystem, making them valuable for both ecological studies and sustainable fishing practices.