When you think of a hero — a soldier, firefighter, or Marine — what image pops into your head? Do you think of a shaved chest, chiseled abs, and vein-covered arms? Or do potbelly, 12-inch arms, and acne seem more appropriate?

Most civilians (particularly those who don’t know many military personnel) probably have a pretty good idea of who comprises our armed forces. After all, we tend to see pictures of guys in full combat gear in the news and strong-jawed defenders of liberty in the latest military blockbuster from Hollywood. The problem tends to be the select group that makes the front page combined with the impressive visual effect of all that gear. Spend some time at Camp Fallujah or one of the other main bases and you may end with a different impression of our men and women in uniform. There seems to be no end to the variety in shapes, sizes, and hairiness of those stationed in-country. After carefully examining the population, however, a few camps appear with enough frequency to merit a general description: basically, you have four main groups of military personnel here and — having traveled in Al Anbar as well as central Iraq — they seem to recur predictably wherever Marines comprise a sizable chunk of population.

The first Marine is the Newbie: he’s usually very skinny (having recently graduated from basic training), around the age of 18 or 19, covered in zits, and awkward. Most people who saw him would probably say, “You should be asking for my fast-food order, not defending the country.” A Newbie can usually be seen trying to ingratiate himself to larger, more confident members of his platoon or squad, or occasionally foraging tentatively for food around the chow hall, much like a small, furry woodland creature. Paradoxically, he is often a great guy to have in a firefight, being freshly motivated and trained, and with today’s operational tempo, he may already have been in Iraq or Afghanistan and gained some experience.

The second Marine is the Gear Freak: no one is really quite sure what he’s capable of, but he seems to think the most important part of life is being prepared for any and every eventuality. He is loaded down with knives, magazines (for bullets, not reading), omnitools, flashlights, carabineers, and myriad other tactical stuff; he has pretty much transformed himself into a giant, walking Swiss Army Marine. All you have to do is pick the right area of his body, gently apply pressure, and the tool you need just pops out. Many are easily recognizable by their aviator-type sunglasses, but watch out for a lot of muscle because he could also be a War Dog (see below) who has seen Top Gun too many times.

The third Marine is the Fat Guy: he really has no place over in Iraq (if you believe it’s a desert combat zone), but here he is. This is not to discriminate against him based on weight; it’s usually more a function of his ability — or lack thereof — to move quickly with a combat load. If you wonder how he’s able to maintain his comfortable waistline, look no further than his desk and the chow hall; the sheer quantity of food available staggers the mind, and self-control is all that stands between Fat Guy and his nefarious cousin, Fatter Guy. He may actually enjoy being deployed in some cases — especially if his family life isn’t too good — because work (for these guys) tends to be logistical support with no real chance of being killed or wounded, and 140 degrees Fahrenheit is only a number when you have air conditioning. For all intents and purposes, what Fat Guy does could be misconstrued as any number of office jobs back in the States.

The last Marine is the War Dog: he tends to be very well-built, with almost no body fat, and is most often found working out in the gym with what appears to be a baby’s “onesie” on, allowing everyone to marvel at his muscularity. As far as anyone can tell, this is essentially the same guy you see in Hollywood taking care of terrorists (both regular and bearded varieties), lava monsters, and Democrats; you’ll remember him somehow ending up on a tropical island with one or more nude women. What’s funny about this guy is even though Marines should know better (the only way you could have that much time to work out is if you weren’t actually in the fight for sustained periods of time), they still believe he’s the model of the Marine Corps like so many starry-eyed civilians do. This misconception wouldn’t be so bad if it didn’t cause a lot of deployed Marines to worry about their appearance and defending their country’s interests overseas: Have you ever tried hunting down terrorists on the South Beach diet?

Obviously there are plenty of servicemembers who don’t fall into any of these categories, but you can find some part of one or more of these characters in just about every Marine swaggering around an FOB, COB, COP, camp, base, station, city, village, hamlet, or commune. Just don’t call them by the names given them here; they’re still Marines and can probably kick your ass (yes, even Newbie).