More recently, members of the group -- known as the Shadow Wolves -- have been taking their unique skills to Eastern European and Central Asian states to train border officers there, using methods based on traditional Native American tracking.
A Shadow Wolves team recently spent a week in Moldova introducing local border guards to their unconventional ways.
Kevin Carlos is a Native American of the Tohono O'odham Nation. He spoke about the program in an interview with RFE/RL in Chisinau.
"The program here I believe was very successful. We worked with the Moldovan border guards. Not only were we here to train them, we were also here to learn from them, as well. This is their area, their terrain. They know what's out in their green forest. We explained we're here not only to teach but to learn -- please give us the information that you know about tracking in your area and we'll tell you our knowledge, and you'll combine the whole effort yourselves," Carlos said.
Moldova faces huge problems with illegal migration, as well as drugs and arms trafficking, via its porous eastern border, which is under the control of its separatist Transdniester region.
When asked about the specific situation at Moldova's eastern boundary with Transdniester, a U.S. Embassy press attache present at the interviews said that was a subject the members of the group were not prepared to talk about.
At the same time, Moldova is trying to tighten security at its western border, which is set to become the European Union's easternmost boundary when Romania joins the bloc, as early as 2007.
Tony Karb, a U.S. Customs Service senior adviser in Moldova, told RFE/RL that modern technology has limits when it comes to effective border protection.
"There's only so many things you can do with sensors. You have to rely on common sense and human beings to do the best work. Here in this part of the world, they use dogs, but sometimes the dog can only work so many hours. And it takes a combination of a dog and a human being to work together as one machine to track an individual and stop illegal migration or movement of contraband or other things," Karb said.
The Shadow Wolves came into being in 1972 in the southwestern U.S. state of Arizona and were originally formed to stop drug trafficking and illegal migration across the border between the United States and Mexico.
The Shadow Wolves use the skills many of them learned in childhood -- tracking game or finding free-ranging livestock that may have wandered away. Small details such as broken twigs and branches or overturned rocks -- which may pass unnoticed to the untrained eye -- are precious indicators of movement, time, and direction to the Shadow Wolves.
The Shadow Wolves currently number 21 people -- 19 men and two women -- from a diversity of Native American nations.
The unique tracking skills of the Shadow Wolves have been used over the past several years to help some governments in the former communist bloc better protect their borders.
Many of the countries the Shadow Wolves have visited face problems with stemming human trafficking, as well as with drugs and arms smuggling.
Carlos says Moldova is the ninth country where the Shadow Wolves have helped train local border guards -- and that other countries may follow.
"So far, we have been to Latvia, Lithuania, Estonia, Poland, Croatia, Uzbekistan, Kazakhstan, and Turkmenistan. The program is offered, and if the host country invites us, we would love to go. No immediate plans, but if anyone invites us back, we would love to go," Carlos said.
Another member of the team, Gary Ortega, also of the Tohono O'odham Nation, points out that working abroad poses different challenges for the Shadow Wolves.
"The terrain here is a little bit different than the terrain back home, as far as the trees [are concerned]. Whereas back home, we work in the desert. So here, when I come on these trips, it always reminds me to be a little bit more patient. If you try to track too fast, you're going to end up losing those things that you're looking for," Ortega said.
Few members of the original Shadow Wolves unit are still on active duty. New, younger trackers are replacing the older officers. These new recruits also travel abroad to learn from the training sessions the Shadow Wolves conduct in different countries.
Here's the youngest member of the Shadow Wolves team, who traveled with other members of the team to Moldova.
"My name is Sloan Satepauhoodle. I am with the Kiowa tribe, which is originally from the state of Oklahoma, and this is my first trip. So I'm just trying to learn about the program, what we're doing. I'm just kind of trying to get the background on how the process works," Satepauhoodle said.
But why this name, the Shadow Wolves? Officer Kevin Carlos explains: "The idea behind the Shadow Wolf name came from one individual. His name was Stanley Liston, a phenomenal [Native American] tracker. This man, he would mimic the movements of a violator walking through the area. We called him the Shadow Man. [And] we called ourselves the Shadow Wolves after his name, the Shadow Man. We thought, like, we would go out individually, locate a violator's location, track him down. And as we were doing so, we would call in the rest of the guys -- the rest of the pack -- and make a big old 'wolf pack,' so to speak. That's where the name came from -- the Shadow Wolves."