LORDSBURG, New Mexico (Border Report) – Agency lore states that when Congress founded the U.S. Border Patrol in 1924, there were two requisites to join: Grab your gun and bring a horse. Although things really were not as simple, the fact is that a century later, border agents are still patrolling the U.S.-Mexico border on horseback, looking for contraband, apprehending unauthorized crossers, and saving people in distress. Border Patrol horse patrol agents watch over 4,000 square miles of desert, brush, rocky trails, and rugged mountains in the Boot Hill region of southwestern New Mexico. Their day starts at 3:15 a.m. by cleaning stables and prepping horses for the long ride. When an underground sensor goes off along well-known smuggling routes near the border, the horses go up in trailers, and the agents speed up to the nearest town. Once on the saddle, pursuits can last days. On Thursday, horse patrol units tracked a group near Animas. Some of the migrants might be wearing sweatshirts on a morning when the wind chill hovered just above freezing. "Our job is to be out here catching people coming in illegally, but at the same time, we don't want anything to happen. They're human beings the same as us," said Border Patrol horse patrol member Brandon Packouz. The migrants passing through Boot Hill – an area roughly the size of Connecticut – endure a grueling journey. They are brought across from Mexico by smugglers in Agua Prieta to the west and Las Chepas and El Berrendo to the east. It's a five-day walk from there to Interstate 10 near Lordsburg, and vehicles are waiting to take them to Phoenix or Los Angeles, border agents said. It's not unusual for smugglers to abandon the group mid-way or just point them in the right direction and leave once they're on U.S. soil. Border agents said they've already charged their fee and don't care who makes it or not. Packouz saw a migrant woman go down in triple-digit heat last summer and watched a colleague who also is an emergency medical technician rush to render aid. The natural tension of meeting individuals seeking to evade apprehension often turns into a sense of urgency to save a life. The EMT managed to bring down the woman's temperature, and the agents brought her and the group down to waiting Border Patrol vehicles. "It feels good when you rescue someone and get them out of this country because this country is rough," Packouz said. "Get them out of here alive and safe even though we're returning them to the country they came from. They get to get back to their families." U.S. Customs and Border Protection spokesman Landon Hutchens sees a continued need for the horse patrol. "The mountains and desert terrain often lack roads and formal infrastructure. It isn't easy sometimes, even with all-terrain vehicles. The horse patrol can access areas of canyons and mountains that otherwise would be unable to be patrolled," he said. Riders, mounts work as a team Jonathan Miller is a horse instructor at the Border Patrol Lordsburg station. His priority is keeping the mustangs and thoroughbreds healthy and teaching new agents to keep their emotions in check. A horse makes a loyal, disciplined companion but you cannot expect a 1,200-pound animal to behave like a pet. “Our relationship with our horses is not much different than any other agent. They’re our partner out there (but) every horse is different, different personalities, different abilities […] and it’s important for us to know what that horse is capable of and what his limits are. They kind of learn ours, too. They teach you a lot about yourself,” Miller said. When an agent volunteers and is approved to join the horse patrol,  basic training is four weeks with additional two-week field practicum, Miller said. There is classroom instruction, supervised riding and an obstacle course preparing the rider to negotiate the rocks, brush and hills of New Mexico. Miller said about half the agents come from a horse background; the rest must learn “how not to run over someone on the field or at a parade.” Miller has been working with horses for 14 years. He is diligent about the grooming the 20 mounts under his charge and enjoys seeing them sprint out of the stable and into the backyard. He said the ranchers in Boot Hill welcome the horse patrol passing through their property a lot more than if an agent showed up in a noisy ATV. “Both are effective, but we don’t make noise. If you are in a situation that you have some narcotics smuggler and you don’t want them to know you’re coming, it’s a lot more effective on a horse,” Miller said. The animals become a safety blanket for Border Patrol agents who might end up tracking unauthorized border crossers by themselves – as the units spread out to cover more ground. The migrants and even smugglers generally react with respect when an agent on horseback approaches. “They might have fear; they might come from a ranch and see a big cuddly teddy bear, but they all have a bit of respect when you show up,” Miller said.