They do. technically the USMC is part of the Navy Department, as for many decades the Air Force was part of the Army ( no longer true=but look at the song!)
Spanish Navy Marines was created in 1537.
They are their own service. They're administered under the Department of the Navy.
None. Navy Seals are all Navy. Marines are a completely different branch of military.
The Esperanto word for navy is mararmeo but there is no word for marines in Esperanto.
This may come as a shock to you, but the US Navy SEALs are under the Navy and not the Marine Corps
The motto of Spanish Navy Marines is 'Per Terra et Mare'.
No, Marines are not considered part of the Navy. While they fall under the Department of the Navy and share some administrative functions, the Marine Corps is a separate branch of the military with its own unique missions, capabilities, and command structure.
You let your enlistment with the Navy expire and then join the Marines. There is no 'transfer' between the two units. If you are a Corpsman, you can be asked to serve with the Marines.
The Navy
The SEALS are a US Navy unit. The Marines have their own special forces, Recon. They may cross train, but they have different missions and skill sets.
The Corps was created as the Continental Marines in 1775 to provide Naval Infantry for the US Navy and to project Naval Power to the four corners of the earth. It was a tough task since the Navy did not own a Ship of the Line at the time.
The U.S. Marines is a separate branch of the military, independent of the U.S. Army. While both services are under the Department of Defense, the Marines operate as their own distinct force within the Navy. They have their own training, equipment, and mission focus.