25 years ago in a small colonists' settlement called Calamar in Colombia a group of about 40 indigenous people wearing no clothes and speaking a language no one could understand turned up on the doorstep of the local school. Who were they? Their dramatic arrival sparked something of a sensation in Colombia's media, concern from Calamar locals, and headaches for the government's indigenous affairs department in Bogota about what, if anything, to do. It didn't help that no one understood what they were saying, or what they wanted or where they were going, and when a group of indigenous interpreters were flown in, speaking 21 languages between them, they couldn't understand either.

The people who appeared that day, in 1988, were the Nukak, members of an indigenous people living in small, highly-mobile groups (e.g. the wayari muno, meu muno, mipa muno) to the east of Calamar between the River Guaviare and River Inirida in Colombia's Amazon. According to a 2011 book called, in my English translation, The Nukak: The Last Nomadic People Officially Contacted in Colombia – edited by two Colombian anthropologists, Dany Mahecha and Carlos Franky, who speak the Nukak language – that day in Calamar was the "definitive event" marking the Nukak's official, permanent contact with national society.

There are various theories about why the Nukak turned up like that, but as Mahecha, Franky and other contributors imply, it wasn't so much them arriving on Calamar's doorstep as the other way around. The Nukak found themselves:

… on the frontier of a rapidly-advancing colonization involving the illegal cultivation of coca … [and] were greatly outnumbered by campesinos – estimated to number 10,000 around their territory when 'official' contact was made … Encounters [between the Nukak and colonists] became more common as the frontier advanced, particularly because this involved the colonists destroying places that were important to the Nukak – their gardens, fruit trees and areas with particularly high numbers of palm trees – to make way for their farms … The arrival of various Nukak families at Calamar in 1988 was the definitive event marking the clash between Nukak territory and the colonial frontier.

As this suggests, and as Mahecha et al acknowledged, there had been some contact pre-1988. This included peaceful encounters and violence in 1965, further encounters from 1986 onwards, and the secretive arrival in Nukak territory, all the way back in 1971, of Christian missionaries from the US-based New Tribes Mission who subsequently spent enough time with the Nukak to make them, ironically, the only people who could communicate effectively with them in 1988.

What has happened in the 25 years since official contact? Within the first five years approximately 40% of the Nukak died, the coca frontier continued to expand into their territories, and they have found themselves engulfed by a civil war between the Farc, in the region since at least 1985, and paramilitary groups who "between 2002 and 2004 together waged an intense war for control of the middle River Guaviare", according to Mahecha and Franky, and which was escalated between 2003 and 2007 following the arrival of Colombia's army.

Largely as a result of this conflict, since October 2002, members of the vast majority of the different Nukak groups have been forced to abandon their territories, either seeking refuge in areas belonging to other groups or on the outskirts of a town called San José del Guaviare. Between 2002 and April 2008 there were numerous Nukak exoduses, and at one point, in mid-2006, according to Mahecha et al, 35% of all Nukak were living in or near San José in two settlements, Agua Bonita and Villa Leonor.

Conditions in these settlements, generally speaking, have been extremely poor. There isn't enough space to hunt, fish, gather, or plant gardens, and, despite some state food packages and medical attention, "the Nukak have often turned to begging for food, clothing and money" in San José and "reports of prostitution, sexually-abused children and petty theft continue", according to Mahecha et al.

What, you might ask, does this have to do with Niall Ferguson, a British historian and Harvard University professor who was once named by Time magazine as one of the 100 most influential people in the world? In his 2008 book The Ascent of Money: A Financial History of the World – in what appears to be an attempt to illustrate the "considerable disadvantages" to the "cash-free life" of "hunter-gatherer societies" – Ferguson wrote:

Five years ago, members of the Nukak-Maku unexpectedly wandered out of the Amazonian rainforest at San José del Guaviare in Colombia. The Nukak were a tribe time forgot, cut off from the rest of humanity until this sudden emergence. Subsisting solely on the monkeys they could hunt and the fruit they could gather, they had no concept of money. Revealingly, they had no concept of the future either. These days they live in a clearing near the city, reliant for their subsistence on state handouts. Asked if they miss the jungle, they laugh. After lifetimes of trudging all day in search of food, they are amazed that perfect strangers now give them all they need and ask nothing from them in return.

This is absolute nonsense. Leave aside Ferguson's use of problematic terms like "hunter-gatherer societies" or his claims about monkeys, fruit and the future. More important is the fact that, by 2003, members of the Nukak had had contact with Christian missionaries for 30-odd years; many had seen huge swathes of their territories invaded and destroyed to grow coca, as well as graze cattle, to meet distant consumer demand, and many had been effectively made refugees by a civil war. Didn't Ferguson think to mention any of that? Indeed, the Nukak had experienced a "demographic catastrophe", as Carlos Franky calls it in his 2011 Phd thesis, with approximately 40% dying 10 years before "this sudden emergence" and "unexpected wandering" even took place: hardly "a tribe time forgot," as Ferguson calls them, "cut off from the rest of humanity …"

Equally misleading, and perhaps more dangerous, is Ferguson's implication that the Nukak don't miss the rainforest and prefer San José. As Mahecha et al have acknowledged, there are some Nukak who prefer the town to their territories, but they also make it clear that many Nukak want to return home, that doing so is "constantly discussed", and they have tried again and again but have often been blocked, mainly by the Farc. For example, attempts were made in 2003, 2005, early 2007, mid-2007 and 2008, and in mid-2006, as a kind of compromise measure, the Nukak were moved nine miles east of San José near a colonists' settlement called Puerto Ospina, which they later abandoned. Wrote Mahecha et al in 2011:

The wayari muno in Agua Bonita and the meu muno in Villa Leonor have made it clear they want to return to their territories and suggested that they receive medical attention, education and support obtaining tools, seeds and food hand-outs – before their gardens can be cleared or recovered, planted and harvested – when they arrive there. These suggestions have been made by the Nukak several times in the past, and any decision they make about returning will largely depend on them being heeded.

And now, two years later? Some Nukak have managed to return home, but most haven't and the exoduses continue.

In June this year approximately 30 Nukak families turned up at San José seeking health support – given that medical teams can't otherwise reach them – and refuge from the armed conflict. About two-thirds of these families have since returned, but most of the rest were relocated about an hour and a half from San José in late November and, according to Mahecha, there are still about 180 Nukak, out of an approximate total of 650, in the town or on its outskirts.

"The meu muno finally managed to return to their territories in 2011 and 2012, but the majority of the wayari muno are still forcibly displaced and face the same problems," she says now. "The older Nukak still hope to return one day, although the younger generation who have grown up displaced have begun to question it because of fears for their safety, including forced recruitment [by illegal armed forces] and minefields."

• This blog was amended on 23rd December 2013 to remove inverted commas around the word 'historian' in the standfirst