German Shepherd

The German Shepherd was a breed of domesticated dog originating from Germany on Earth.

After being sent back in time to 1947, Odo stayed out of sight by posing as a German Shepherd employed as a security dog by the United States of America Army Air Corps. 

A German Shepherd was serving with a security guard aboard the USS Enterprise (CVN-65) in 1986 when Chekov and Uhura sneaked in to collect photons from the ship's nuclear reactor. 

An angry German Shepherd tried to keep the crew of the USS Voyager away from the barn aboard the Caretaker's array so they wouldn't find out about the true nature of the space station.