[3][4] Historians estimate that the genocide spanned a period of between ten and twenty years, and resulted in the decline of the Selk'nam population from approximately 4,000 people during the 1880s to a few hundred by the early 1900s.

[5][6] During the late 19th century, European and South American livestock companies affiliated with the Chilean and Argentinian governments began to establish estancias (large ranches) on the Isla Grande de Tierra del Fuego, which along with the Tierra del Fuego gold rush displaced the indigenous population and heavily disrupted their traditional way of life.

[7] In response to violence between non-indigenous settlers and indigenous people, a campaign was conducted by European and South American hunters, ranchers, gold miners and soldiers to exterminate the Selk'nam.

Eventually, the Chilean and Argentine governments issued land grants to the Salesians of Don Bosco, allowing them to establish several Christian missions to "save" the remaining Selk'nam, who were deported to Dawson Island.

[11] The Selk'nam had lived a semi-nomadic life of hunting and gathering in Isla Grande de Tierra del Fuego[12] for thousands of years.

[15] There are difficulties in obtaining reasonable estimates of the population of the three Selk'nam groups, due to the lack of demographic studies prior to colonization.

In the memoir of the Governor of Magallanes Manuel Señoret [es] (1892-1897), he stated that: When Tierra del Fuego was barely known, it was believed that the number of Ona Indians was very small.

That is to say, that at the end of the 19th century, there were about 783 Onas left in Tierra del Fuego.These figures show that the population could have been quite close to Martín Gusinde's estimates of 3,500 to 4,000 on the whole island.

[21] The Chilean expedition of Ramón Serrano Montaner in 1879 reported the presence of significant gold deposits in the sands of the main rivers of Tierra del Fuego.

Though gold miners did play a role in the violence against the Selk'nam, the majority of attacks as part of the genocide were committed by South American and European ranchers and hunters, with the collaboration of Argentinean and Chilean governments and the Salesian missionaries.

[24][25] Large companies paid sheep farmers or militia a bounty for each Selk'nam dead, which was confirmed by the presentation of a pair of hands or ears, or later a complete skull.

"[27] The colonial authorities were aware of the indigenous group's plight, but sided with the ranchers' cause over the Selk'nam's, who were excluded from their worldview which was based on concepts of "progress" and "civilization.

Considerable numbers of foreign men were hired and quantities of arms were imported for these campaigns, to eliminate the Selk'nam, who were perceived as a major obstacle to the success of colonists' investments.

[citation needed] Special attention was paid to these events after the intervention of the Salesian missionaries, who condemned the actions of the ranchers while themselves contributing in more subtle ways to the extermination of native cultures.

[40] Later conflicts between governor Señoret and the head of the Salesian mission José Fagnano [es][41] only served to worsen, rather than improve, conditions for the Selk'nam.

[42] Beyond the spread of disease, massacres, and the campaign of extermination, another tool in the genocide was the forcible adoption and assimilation of Selk'nam children into European families.

The perpetrators of the expeditions, such as owners and stakeholders of farms belonging to Mauricio Braun, José Menéndez, Rodolfo Stubenrauch, and Peter H. MacClelland, were never prosecuted.

Even official figures and civil servants, like governor Señoret and José Contardi, who theoretically had the greatest responsibility to guard the sanctity of the law, were never investigated.