But others had no experience. "This is all new to me," said Cpl. Bradley Neuenburg, a 20-year-old computer buff from San Rafael in Northern California. "I'm more used to basic syntax, binary language and codes."
"Pull that rope tight," Sgt. Graham Golden told Neuenburg in a voice loud enough to be heard by others having the same difficulty. "You're not going to hurt the mule, and otherwise that load is going to fall off up the mountain."
After several days of learning to handle rope, tie knots and hitches, and pack and balance loads, the students were graded on the knots -- and their demeanor around the animals.
"It's a dying skill that we need to revive," said Sgt. Jerry Meece, 35, a lean, slow-talking native of Lufkin, Texas, who was a rodeo bull rider for a dozen years before enlisting.
The animal packers course dates to the 1980s, when the CIA sent operatives here before they were dispatched to help the Afghans fight the Soviet occupation force. The agency bought several thousand mules for the Afghans to maintain supply lines.
When they reach Afghanistan, the Marines probably will work with donkeys, which are cheaper and more common. A good donkey can be had there for $5.
As the Marines prepared for their first "hump" up the mountain, instruction was intense, laced with an obscenity that is integral to military patois. Golden spotted Pfc. James McGuckin, an 18-year-old from Staten Island, curling a rope around his hand and forearm like a suburbanite wrapping a garden hose for storage.
"Is that the way I taught you to handle ropes?" he bellowed, slamming his clipboard to the ground. "Pay attention to detail! Are you a [expletive] Marine or in the [expletive] Army?"
In combat, said Golden, 27, of Ferndale, Ark., any deviation from training can get Marines killed.
McGuckin froze to attention and carefully placed the rope on the ground. Other Marines watched wordlessly -- seemingly relieved it was someone else who was the object of their teacher's ire.
Later, as he waited in line at the chow hall, McGuckin said he did not mind being bawled out. "Someday, when we're in a fight, we're going to need those animals and those ropes," he said.
The trek up the mountain to a grassy meadow the Marines call LZ (Landing Zone) Penguin came on the fourth day. The rain of previous days had abated, and only a few clouds shielded the Marines and the animals from bright sunshine.
The Marines and animals trudged for more than three hours and three miles up narrow, rock-strewn trails, a climb of about 1,000 feet in altitude.
More arduous journeys would follow in the next eight days. One would test the Marines' ability to use their animals to retrieve U.S. injured and dead from a helicopter crash, with 200-pound dummies called Rescue Randys as faux casualties.
The mules were purchased by the Marines from an outfitter in Montana. The donkeys were rounded up by the Bureau of Land Management from its vast acreage.
The mules -- bigger, sleeker and more cooperative -- led the single-file procession. The donkeys were in back. The Marines devised different strategies for their maiden convoy.
Lance Cpl. Usay Vue, 25, of Fresno, put apples from the chow hall in his backpack. His mule, Gray, could smell the fruit and nosed the pack. He seemed to be imploring Vue with a longing look in his brown eyes.
As they waited in the corral for the order to move out, Vue gave in and fed the mule a slice.