The Germans did not call the Marines Devil Dogs. That is a myth. The US press called them that and just as the Marines have always done, they changed the facts to suit the image of themselves they want the world to see.
At Bella Wood Masacre
US Marines..Germans called them "Devil Dogs".
Jarhead, Leatherneck Devil Dogs
the nickname given to the US Marines is Jarhead
The Marines in World War 2 were called Jarheads, Devil Dogs, leathernecks. Germans were referred to as Jerrys and Huns.
Supposedly a term used by Germans when describing the fighting spirit of the Marines they battled at Belleau Wood, France in June of 1918 during WWI. However this is the history taught by the Marines and may be nothing more than a legend.
"Persons who are not native to the US."
U.S Marines (jarheads, devil dogs) This answer by a Devil In Baggy Pants
The doberman is often used in the marines. They are very easy to train and are the most intelligent dog, but are very aggressive and vicious.
I do not know what soldiers were called but after the U.S. Marines 2nd and 3rd division utterly crushed the German 237th, 10th, 197th, 87th, and 28th Divisions in 26 days at the battle of Belleau wood; with the terrain, German use of large quantities of mustard gas, French retreat, and manpower all in favor of Germany. The Germans began calling Marines, Teufel Hunden which translates to Devil Dogs for the terrifying ferocity of Marines relentless style of fighting with no mercy down to bloody hand to hand combat. A name which is in common use among Marines today.
They became known as the Devil Dogs in the Battle of Belleau Wood during Wprld War One.
"Doughboys" was the accepted term. While some historians question the validity and veracity of the claim, the US Marines also claim the title of "Devil Dogs" (teufelshunde) was a name given them by the Germans for their defiant actions at Belleau Wood.
TeufelHunde in German, or in English, Devil Dog. A head banging tribute to the fierce fighting style of the U.S. Marines. The title "Teufelhunden" translates into "Devil Dogs", and it is the nickname German soldiers gave to Marines during the battle of Belleau Wood in 1918 by an offical report. Ever since, the nickname Devil Dog has been common in the United States Marine Corps. THEY ALSO CALL US. DEVIL, KILLER, DEVIL PUPS (YOUNG MARINE CHILDREN), HARD DOGS, AND A FEW JUST TO NAME A FEW Often referred to as Jarheads. You can call a woman marine a BAM - if you want to carry your teeth home in your pocket! M-A-R-I-N-E-S= Muscles Are Required, Intelligence Not E-Sential. Gyrenes - a term the Navy came up with to insult the Marines, but they liked it Uncle Sam's Misguided Children Also leathernecks -- from an archaic uniform no longer in use (same with jarheads).