today's naval special warfare operators can trace their origins to the scouts and raiders, naval combat demolition units, office of strategic services operational swimmers, underwater demolition teams, and motor torpedo boat squadrons of world war ii. in the vietnam era, the navy drew most of its seals from the underwater demolition teams; from the early 1960s up until 1983 the seal teams and udts coexisted. navy seals typically traced their origin to the scouts and raiders while the underwater demolition teams traced theirs to the navy combat demolition units (the navy drew its udts from ncdus). however, in 1983 the underwater demolition teams were merged with the seal teams. this, in turn, merged their ancestry. while none of those early organizations have survived to present, their pioneering efforts in unconventional warfare are mirrored in the missions and professionalism of the present naval special warfare warriors.