Military Working Dogs have been used by the U.S. Military since WW I. The German Shepherd is the most frequently used dog in the military. These dogs are commonly referred to as War Dogs; however, the correct term is Military Working Dogs. There is a confirmed list of 3,747 dogs that were used in Vietnam identified by Dr. Howard Hayes, Veterinarian (RET) of the National Institute of Health by "brand number" (a tattoo usually placed in the left ear of the dog). However, Records of the dogs in Vietnam where not maintained by the military prior to 1968, thus the discrepancy.

How many handlers served in Vietnam and what branch of service?
All four branches of the military used dogs in Vietnam. Approximately 10,000 handlers served. Vietnam was the largest concentrated effort of the use of dogs and handlers in any Combat Era the United States has ever undertaken. It is estimated that the dogs and handlers saved over 10,000 lives.
The following is a breakdown of handlers by Military Branch that
served in Vietnam. 65%Army, 26%Air Force, 7%Marine, 2%Navy.

What mission (duties) did the dogs and handlers have in Vietnam?
> Scout Dogs
A Scout Dog Team consisted of one German Shepherd and the handler.
> Combat Tracker Teams
The Tracker Team consisted of a Labrador Retriever (Sometimes
Shepherds) and handler, a cover man, a Visual Tracker and a Team Leader. Trackers were called to duty when the unit wished to re-establish contact with the enemy.
> Sentry Dog Teams

Sentry Dog Teams, "walked the wire" on the outskirts of a location and their primary form of communication was via radio after the dog alerted. Sentry Dog Teams were the first line of defense on the perimeter of not only Bases in Vietnam but also ammo depots, supply areas, communications areas, naval installations, camps, flight lines, and other sensitive areas.