The Aguaruna are known for being fierce defenders of thier culture

The Aguaruna have always been hostile to outsiders. When the Inca Empire covered much of modern Peru, Ecuador, Chile, and Paraguay Aguaruna territory was an impenetrable pocket of resistance. When the conquistadors came from Spain, they easily overturned the Inca Empire, which had been weakened by a civil war over succession to the throne. The Spanish were no more able to conquer the Aguaruna than the Incas.
The Spanish found the Aguaruna territory hostile. It is rugged terrain; much of it covered by dense jungle, with extreme temperatures and unfriendly wildlife. There are tarantulas that emit a powder than blinds for days, as well as flesh eating piranhas, and yellow, white and black cayman (a type of alligator) which can grow to 2-4m. The Aguaruna were even scarier than the wildlife. They were fierce warriors, who would remove the heads of their foes after battle. They then shrunk the heads, using a method that involved curing, boiling and roasting. These shrunken heads, worn around the neck and known as “tsantsa,” were believed to contain the soul of the person killed.
The Aguaruna success in keeping out foreign intruders later led to some problems. The Spanish colonialists created many of the borders that divide the modern states of the region. The border between Ecuador and Peru runs directly through the heart of Aguaruna territory. Before 1941, the Aguaruna were able to move freely between the two states, oblivious to their existence, and unconcerned with political boundaries. Others, namely the governments of Peru and Ecuador, were quite concerned with this border.
The Spanish had never been able to penetrate Aguaruna territory, and hence had been unable to map out a 75-mile area that included where the Peru-Ecuador border would fall. In 1941 a war over this border began, a brutal and ugly conflict fought on Aguaruna land. Later that year, the two sides met in Rio de Janeiro, hoping to settle the dispute. They both signed a treaty known as the Rio Protocols, which was supposed to end the war, but did nothing of the sort. While they were able to agree on 95% of the border, 5% was left in dispute. This 5% was the area of the Cenepa River, the area that ran through the Aguaruna land. This area was to be fought over for more than fifty years, with hostilities flaring up intermittently, most notably in 1981, and 1995. No peace treaty was signed until 1998; it had been the longest running border conflict in the Western Hemisphere.
During the conflict, the border was closed. Aguaruna were unable to visit friends and family who lived across the border. More than 20,000 Aguaruna villagers were displaced by the fighting, and at least 28 were killed by stepping on land mines, between 130,000-150,000 of which were planted by both sides throughout the border region. The war wreaked havoc on the natural resources of the area. Chemicals from exploded and unexploded munitions contaminated rivers. Acres of rainforest were cleared for troop transport and the building of military bases.
The Aguaruna suffered another environmental disaster in the mid 1990s when potential oil reserves were discovered in northern Peru. Oil companies rushed in eagerly, destroying the rainforest by the hundreds of acres, often using TNT, in order to build paths and heliports. This wanton disregard has been very troubling for the Aguaruna. They have been, for centuries, ardent conservationists of their portion of the Amazon. In order to survive in such a remote and apparently inhospitable region they have had to carefully adapt to and respect the unique ecological balance.