Dog tags are part of the uniform of every member of the US military. According to the Army, their primary purpose is "to help identify remains of the fallen." The tags are simple pieces of metal stamped with the name and other identifying marks of an individual soldier, sailor, airman or marine, but in the event of a service member's death, they can become potent emotional symbols.
Metal "identity disks" were first issued to U.S. soldiers in 1899, during the Spanish-American War. They became a regular element of U.S. military uniforms in 1908.
All U.S. dog tags include the owner's name, Social Security number, blood type and religion. In addition to that basic information, each of the armed services uses a slightly different format for its dog tags. Marine Corps dog tags, for example, include gas mask size. A red dog tag is used to alert medical personnel to allergies or other medical conditions.
The main purpose of dog tags is to help identify the remains of deceased soldiers, sailors, airmen and marines. Service members are issued two tags so that in the event of death, one tag can stay with the body while the other is collected for record-keeping purposes.
Dog Tags in Other Countries
While the U.S. issues service members two tags containing identical information, many other countries, including Canada, Israel and Germany, issue their soldiers and other servicemen a single tag that has all of the information printed on it twice. In the event of the soldier's death the tag is designed to be broken in two: one half remaining with the body and the other being collected for record-keeping.
The Army credits newspaper publisher William Randolph Hearst with coining the term "Dog Tag" in the 1930s.