A quahog (pronounced KO-hog) is a type of large, hard-shelled clam found along the Atlantic coast of North America, from Canada down to Florida. These round, thick-shelled clams live buried in sand or mud in shallow coastal waters, where they filter tiny particles of food from the water.

Quahogs have been an important food source for thousands of years. Native Americans ate them, used their shells to make tools, and created valuable purple and white beads called wampum from the shells.

Today, quahogs appear on restaurant menus under different names depending on their size. The smallest are called littlenecks, medium ones are cherrystones, and the largest keep the name quahogs (though cooks sometimes call them chowder clams because they’re often used for making thick, creamy New England clam chowder). If you’ve ever had clam chowder or stuffed clams at a seafood restaurant, you may have eaten quahog.

Quahogs can live for over 100 years, and scientists sometimes study their shell growth rings, like tree rings, to learn about ocean conditions from decades past.