I seem to hear a romanticized view of life in North America before the Europeans came. Stories of living off the land, of multiple nations minding their own and of peace. However, there were indigenous warriors. Did indigenous people as fighters really only begin when the Europeans came, or were there wars between nations prior? Maybe only minor squabbles? As well, were nations mostly peaceful or confrontational? What could cause fighting? I know these questions might be difficult to answer because every nation-nation relationship was likely different.
There was certainly warfare in North America prior to European contact. Setting aside the fact that Mesoamerica and its long history of warfare is part of North America, I'll assume the intended focus of your question is North America-north-of-Mexico. In this case we see examples of pre-colonial warfare in oral history, in the archaeological record, and in the peri-colonial wars that were already in progress when Europeans showed up.
Among the most famous bouts of pre-colonial warfare in the region that has been recorded in oral history are the conflicts that preceded the establishment of the Haudenosaunee (Iroquois Confederacy). The root cause of the conflict is uncertain, but given that the among the Great Peacemaker's primary goals in establishing the Confederacy was to create the Condolence Councils and adoption laws to replace Mourning Wars among the member nations, it seems reasonable that the conflicts were a vicious cycle of Mourning Wars (a later bout of run-away Mourning Wars seems to have snowballed into the Beavers Wars of the 1600s). Mourning Wars are generally small-scale conflicts intended to restore the social order after a sudden death in the community. The war party's goal was either to take at least one captive to replace the recently deceased or to kill a member of the opposing community that was believed to be responsible for the death. In pre-colonial and early colonial times these could be very formal affairs, with armored warriors lined up against each other. The advent of the gun brought an end to most Iroquoian armor (the exception being a heavy siege-shield which had been going out of fashion until guns gave it a new purpose) and the old line formations (when formations were used in combat, a more dispersed and mobile U-shaped formation was favored to herd the enemy in particular directions). On a related note, you might be interested in this post on an early colonial war between the Haudenosaunee and the Erie.
Turning further south, Wahunsenacawh, mamanatowick of the Powhatan Confederacy, was quick to ally with the newly arrived English to help deal with threats on three fronts. To the north, he was concerned about Massawomeck raiders coming down the Potomac River and terrorizing the people of the Chesapeake Bay (side note: Chesapeake Bay is named after the Chesapeake people who inhabited the southeastern portion of the bay's mouth, and who were conquered by the Powhatans shortly before the English showed up in Virginia). To the west, the Monacan and the Powhatan were vying for control of rich hunting territory in the Virginian Piedmont. While the coastal Powhatan settlements were dispersed homesteads, the communities close to or in the Piedmont were compact and fortified to defend against the Monacan attacks. Such fortified towns and villages are good archaeological signs that the people who built them felt the threat of war, and they show up elsewhere on the continent as well and at various times. The central precinct of Cahokia was surrounded by a pallisade wall that was rebuilt on three occasions, though we're not sure of the exact reasons why. The Powhatans third major enemy was one freshly arrived from Europe--the Spanish--so I won't go into detail on that one.
Early colonial Florida provides us with two other examples of indigenous warfare. Northern Florida and southern Georgia was dominated by the Timucua when the Europeans arrived. Politically, the Timucua were divided into three powerful alliances. The most prominent of these was Utina alliance dominated the Timucua heartland, flanked by the Saturiwa alliance to the north along the Atlantic coast, and the Potano alliance to the south toward the Gulf of Mexico (it didn't quite reach the coast). The Utina alliance control the main trade route connecting Florida with the Southeastern Mississippians (more on them in a bit) as well as the main local source of stone suitable for making tools. When the French and Spanish showed up in the area, the Saturiwa were attempting to break the Utina's monopoly. The Potano allliance jumped into the war on the Saturiwa's side a little later.
Meanwhile in southern Florida, the Calusa had imperial ambitions. Though the Calusa themselves lived on the west coast around Charlotte Harbor, the dominated the Keys and everything south of Cape Canaveral. The leader of the Calusa received tribute from the leaders of the communities within his dominion, as well as wives to solidify the political connections. When the Spanish showed up, the Calusa were attempting to expand their empire north to Tampa Bay, which was then under the control of four minor polities that jostled among themselves to be top dog in the area. The Calusa didn't attempt to make any alliance with the Spanish at first, heeding the advice of the Taino refugees they harbored and adopting a shoot-first-ask-questions-later policy with the Spanish. But eventually diplomacy was opened up between the Spanish and the Calusa. Their leader converted to Catholicism, married his sister to the governor of St. Augustine, and Calusa traders re-estabilshed relations with Cuba.
During de Soto's entrada through the American southwest, there are more than a few encounters that help shed light on warfare among the Southern Mississippians. One of the leaders the Spanish encounter sought there aid in bringing a rebel vassal to heel, while a rebel vassal of the Quigualtam tried to turn the Spanish loose on his master in a bid for independence. One more than one occasion, the various Mississippian leaders flex their military muscle to de Soto's detriment. At the Battle of Mabila, Tuscaloosa mustered at 2500+ men. Tuscaloosa set a fairly clever trap for de Soto, inviting de Soto into Mabila, a fortified town with his 2500+ hidden in all the houses. Unfortunately, when the trap was sprung, de Soto managed to slip out of the town. Tuscaloosa's forces could not counter de Soto's cavalry in the open fields around the town and were pinned down inside Mabila, which the Spanish set ablaze. It was a Pyrrhic victory for the Spanish, since Tuscaloosa's forces managed to free all the porters and capture all the Spanish's supplies, supplies that were then lost in the subsequent fire or carried off by what few managed to escape.
The last example I'll mention comes just as the survivors of the de Soto's entrada attempted to escape down the Mississippi. Along the way they were pursued by the armada of Quigualtam. Quigualtam brought around 100 war canoes against the Spanish. The largest held up to 60-80 men, sitting three abreast. Those in the middle were armed for close-quarter combat, while the rest were both oarsmen and archers. A smaller three-man canoe was used for reconnaissance, maneuvering close to the Spanish boats before turning to the main fleet. Quigualtam had learned caution from Tuscaloosa's defeat. His fleet approached no closer than their own arrow range, circling the Spanish in an attempt to find a weakness in their defenses and unaware that the Spanish were out of gunpowder and had only damaged crossbows and melee weapons among them. Quigualtam's fleet harried the Spanish like this for a day, inflicting more wounds than fatalities. The following day, a second fleet, about half the size, picked up the chase. This one was a bit more aggressive. They executed well-practiced maneuvers, with some of the warriors aboard the canoe. Of these, some stabilized the canoe while those still aboard provided covering fire for the others that swam head to board one of the Spanish boats and rescue a Native hostage. In a brief lull during this second pursuit the Spanish had to sacrifice their remaining horses, butchering some for meat and allowing a few others to escape when the pursuing fleet caught up with them again. On the third day, the second fleet broke off the pursuit and a third, significantly smaller one took up the chase. The extent and coordination of Quigualtum's push to drive the Spanish out of the Mississippi, like Tuscaloosa's ability to rally thousands of men to his cause, is unlikely to have been military feats conjured up just to fight off the Spanish. Hopefully they give you an idea of the tactics and capabilities the Southern Mississippians had their disposal in times of war.
There were so many Indian nations and tribes it is of course hard to generalize. Conflict existed, for example, between certain Iroquois tribes and the Huron in the St. Lawrence valley area. They did fight over territory and for political reasons, but the arrival of European colonizers intensified pre-existing rivalries. Tribes that came into contact with the Europeans first received a technological advantage over their rivals and an early edge in the fur trade. The Iroquois especially had to adapt to these circumstances and waged wars of expansion to try and solidify their role in the fur trade. I'm sorry if this response is a little vague, luckily the past few decades have greatly expanded our knowledge of pre-settler Indian life.
Richard White- The Middle Ground
Bruce Trigger- Natives and Newcomers
Daniel Richter- Ordeals of the Longhouse
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