The U.S. Marine Corps is trying to play down press reports that its troops suffered proportionately higher casualties in Iraq and Afghanistan than did their army counterparts. Analyzing the raw numbers it was found that .47 percent of all marines who served in Iraq and Afghanistan were killed and 4.28 percent were wounded. The U.S. Army, in comparison, suffered .38 percent killed and 2.75 percent wounded.
The differences result from two unique aspects of the marines. First, they don't have as many support troops as the army. The navy provides a lot of logistical and other support for the marines and its sailors doing this work. A higher proportion of marines are combat troops. But even taking that into account the marines have a higher rate of combat casualties. That is largely caused by a different approach to combat. Marines are trained as assault troops, especially amphibious assault. When attacking a defended beach you have to push the enemy back, so you can bring in your own support forces, or be at a deadly disadvantage. Retreat is not an option.
Even before the marines began expanding and specializing in amphibious warfare a century ago they were aggressive. That's because their main job was close combat. This was in the age of sail, when ships often crashed into each other and the crews fought it out hand-to-hand. The marines were expected to specialize in that kind of combat. The marines were also expected to carry out or lead (sailors armed with rifles) raids ashore. Again, this required aggressive behavior in order to succeed.
The army was trained to carry out more deliberate, less risky, combat. The army fought longer and larger battles. Nevertheless, the army could carry out raids, and often did in Iraq and Afghanistan, but the marines rarely adopted the deliberate "keep our casualties down" type warfare the army favored. The marines believed their aggressive behavior was an asset, and as far as the enemy goes, it was. The marines terrified the enemy more than the army did. But facing either force Islamic militants found themselves dead or running for their lives.
Marine commanders want to keep their casualties down but not at the expense of the aggressive style of combat that has long been what made the marines different from the army.