The United States Navy's Sea, Air, Land Teams, commonly known as the Navy SEALs, are the U.S. Navy's principal special operations force and a part of the Naval Special Warfare Command and United States Special Operations Command.[3] The SEALs duty is to conduct small-unit maritime military operations which originate from, and return to a river, ocean, swamp, delta or coastline. SEALs can negotiate shallow water areas such as the Persian Gulf coastline, where large ships and submarines are limited due to depth.[4]