"You keep using that word. I don't think it means what you think it means." -- Inigo MontoyaI grew up in an area heavily invested in cattle ranching. Although I lived in a city and never had to rope a steer, the culture of cattlemen was deeply embedded into my own from an early age. I don't think I ever realized how deeply this ran until I was older. In situations where cows are involved, I generally know what to do and what to expect. When I find myself having to deal with a cow that everyone else is freaking out about, I am reminded that not everyone was raised around cattle. (For the record: I like cows. I think they're tasty.)
In the parlance, a maverick is a unbranded cow. Usually the reference is to a lost cow, or a very young one. Ranchers like to brand their cattle because there's really no better way to prove ownership. I could chew your ear off telling stories about how rustlers would re-brand cattle in order to change existing brands into other ones. Even so, brands continued to be widespread because of a certain Samuel A. Maverick.
Maverick was one of the earliest Texas pioneers and he started buying up land pretty soon after Stephen F. Austin established his first land grant. He fought alongside the Texians against the Mexican army, and was one of the last people to leave the Alamo alive. He signed the Texas Declaration of Independence, was elected several times to the Texas congress.
At one point during the revolution, Maverick was among a group of Americans captured by the Mexicans and forced into labor camps for over a year. He returned to San Antonio with the chains that had confined him. From the get-go, he is certainly a storied, Texas hero.
Maverick was also a land baron, buying up land at an enormous scale. He ran vast herds of cattle, notoriously without branding any of them. In the day, ranchers didn't use fences and not all of them used brands. Cattle were generally moved in great numbers across the prairie along trails to places where they would be loaded onto trains for the East coast.
Any loose, unbranded cattle near any of Maverick's lands would be rounded up and sent on the trail as Maverick's cattle. Because he was a War Hero, and a Congressman, as well as filthy rich and exceedingly well connected, Maverick could say that all the unbranded cattle are his, and everyone else had to brand their cattle or lose them. It's difficult to say that he didn't make the bulk of his wealth by taking advantage of the poorest ranchers.
So Samuel Maverick was this rich guy who capitalized on his war record to stick it to the little guy. His name is remembered for the trick he used to steal cattle from others. Hmm. Maybe John McCain is a maverick after all.
Incidentally, ranchers finally began using fencing at the convergence of three factors: increasing numbers of farmers, increasing miles of railroad track, and the invention of barbed wire. Before barbed wire, it was too difficult and expensive to build fences that would effectively retain cattle. Cows are big: so heavy that stone fences were required to keep them ensconced -- consequently, no one bothered to fence cattle ranges. (Although they would frequently build stone fences around their homes to keep the cows out of their gardens.)
Fences made moving cattle along the great trails extremely problematic. When farmers started to move out to the prairies and discovered cattle eating their grain and cutting through their fields, they built the first barbed-wire fences. When the cattlemen drove the herds through, they'd cut all the fences along their path -- and the farmers would find hoof prints in their fields again. Only after farmers had developed a political plurality that could compensate for the wealth of the cattle ranchers was fence cutting made illegal and effectively prosecuted. These issues were generally only finally assuaged when railroad tracks were built close enough to the ranchers that the cattle trails became unnecessary.
Today, ranchers use barbed wire mostly to keep cattle off the roads -- but they still brand their cattle to fend off rustlers.