Good dog! Reports have surfaced that a heroic war dog was part of the elite American team that stormed Osama bin Laden's Pakistan compound and killed the terrorist leader. And he's just one member of the U.S. military's four-footed forces. Here, a brief guide to America's canine commandos:

How many war dogs are there?
The Pentagon currently employs some 2,700 dogs, up from 1,800 before the September 11 terrorist attacks. About 600 of those dogs are serving in Iraq and Afghanistan.

How was the dog used on the mission?
He was strapped to a Navy SEAL as the team repelled out of a helicopter, a typical war-dog maneuver. The dog, reportedly trained to sniff out explosives, is believed to have nosed around the compound, looking for explosives and booby-traps. Had bin Laden been hiding in a secret room, the dog could have been used to sniff him out. He could also have chased anyone fleeing the compound. "When the dogs go after a suspect, they're trained to bite and hold them," says Tech Sgt. Kelly A. Mylott, the kennel master at Virginia's Langley Air Force Base.

What kind of dog was he?
Military sources say it was most likely a German shepherd or a Belgian Malinois, another type of large shepherd. Both breeds, the two most commonly used by the military, can run about twice as fast as a human, and, according to a military fact sheet, "have the best overall combination of keen sense of smell, endurance, speed, strength, courage, intelligence and adaptability to almost any climatic condition." That said, Labrador retrievers are also becoming increasingly popular; they're used to check the safety of a route by wandering ahead of a patrol.

What else do war dogs do?
Most are "specialized search dogs," sent ahead of soldiers to find explosives or people hiding. About a year ago, the Marines began developing a new kind of dog called a "combat tracker." These pups are trained to track a specific individual, after smelling a bit of their blood or clothing for reference.

Do the dogs wear special equipment?
Yes. War dogs wear ballistic body armor that can withstand knife attacks, plus other gear to protect them from shrapnel and gunfire. The Navy SEALs recently purchased four waterproof tactical vests designed for dogs. The vests are equipped with speakers, so that handlers can communicate with their dogs from a distance, as well as infrared and night vision cameras that send video back to a handler's monitor, recording everything the dog is seeing. The four special vests together cost more than $86,000.

Sources: New York Times, Slate, American Kennel Club, The Sun