Originally published February 25, 2013 at 2:33 p.m., updated February 27, 2013 at 1:26 p.m.
For decades, the Border Patrol has relied on horses as an old-fashioned, low-tech solution to police U.S. borders.
IMPERIAL BEACH, Calif. -- Two black T-shirts are neatly folded beneath a glass case in the office of the San Diego Horse Patrol unit, located inside a drab brown trailer.
The first shows a cartoon horse. It's baring its teeth, and its eyes bulge ominously. The text below the angry horse, "The Only Working Unit with 1200 Pounds of Muscle Between Its Legs."
Next to it, another shirt features a feisty interpretation of the classic yellow road sign warning against fleeing immigrants: a silhouetted family consisting of a running man and woman. A small girl with pigtails is dragged behind.
But on this rendition of the sign, a man with a cowboy hat on a galloping horse is in hot pursuit behind the family. He's about one stride away from razing them. Above and below the graphic, bold letters read "San Diego Sector Horse Patrol."
For decades, the Border Patrol has relied on horses as an old-fashioned, low-tech solution to police U.S. borders. They offer what the Border Patrol refers to as a "tactical elevation advantage"—that is, agents can see better when they're perched high on horseback.
They also have an edge in terms of longevity. While vehicles last for a few years, a horse can work for up to 17 consecutive years.
And the main draw for horses is that they can go where ATVs and trucks generally can't: up steep rock faces and parsing thick brush. They're also environmentally friendly; and ranchers tend to prefer Border Patrol trespassing on horseback to noisy quads or jeeps.
Supervisory Agent Jaime Cluff of the Imperial Beach Horse Patrol explained how his unit works. "We do exactly what any other agent in any other vehicle does except we do it on horseback," he said. "That is our vehicle."
In recent years, the Border Patrol's use of these four-legged "vehicles" has increased. In 2011, there were 334 horse units in the Border Patrol, according to the Customs and Border Patrol website. That's a 33 percent rise from 2008.
The San Diego Sector has plans to open a second horse patrol facility east of Imperial Beach later this spring, Cluff said. It's supposed to house 8-10 horses.
When the Border Patrol formally began on May 28, 1924, mounted patrols were implemented immediately. A Horse Patrol unit has existed in San Diego since 1979.
The Horse Unit is a highly desirable detail, and a competitive one. Out of the 2,623 agents that comprise the San Diego Sector, just 18 are on the Horse Unit.
Roughly 95 percent of trainees come to the unit without knowing how to ride, according to agents on the San Diego unit like Monica Slack, who also teaches riding.
"The scariest part for someone who’s never ridden a horse before is falling," Slack said. "Because you know, you’re going to fall off. It’s not a matter of if you fall off, it’s a matter of when."
Not only can horses breach difficult terrain, they can also be used as a tool of force.
"To have someone come up on a horse to you, it’s pretty intimidating," Agent Cluff said. "So usually, the people just sit down. You can come up upon a group or whatever you’re working that night, and they don’t even know you’re there."
Although the practicality of using horses is clear, questions surround the actual efficacy of the unit.
Sector-wide, in San Diego, apprehension numbers have plummeted. In 2009, CPB recorded nearly 119,000 arrests. In 2012, the number fell below 29,000.
The Border Patrol says they don't have any releasable statistics about apprehensions and drug seizures specific to the Horse Patrol, or any other unit. The claim lends credibility to a recent GAO report criticizing the agency for an apparent inability to gauge and measure its own performance.
EDITOR'S NOTE: This article has been modified to clarify that the total number of San Diego Sector apprehension numbers dropped significantly between 2009 and 2012.