They are forced to move constantly to escape the bulldozers that raze the Chaco forest in Paraguay to the ground. They are the last members of the Ayoreo people, indigenous forest dwellers also known as the Uncontacted, because they have always lived far from civilisation and its relentless advance.

The forest remains their only home. But the forest is disappearing, at ever-increasing rates. This is confirmed by the study published a few months ago by the University of Maryland, "Global Forest Change", and by the heartfelt appeal of the NGO Survival, which is committed to helping indigenous peoples around the world protect their lands and their rights.

Below, the areas most threatened by deforestation are shown in red.

It all began when Paraguay's Ministry of the Environment quietly decided to grant some cattle ranchers permission to clear a Unesco biosphere reserve, provoking deep outrage from the Ayoreo organisation Opit, which in an appeal to the United Nations Special Rapporteur on the rights of indigenous peoples writes: "For the Ayoreo and their relatives, the protection of the forest and their territory represents life itself."

"For how much longer will Paraguay be able to boast of having two Unesco Biosphere Reserves," said Stephen Corry, director general of Survival International.

These images show how the last strip of forest (in the red square) is threatened by the advance of "civilisation".

The story always seems to be the same. The forest is razed to the ground to make way for livestock farming: "With the highest deforestation rate in the world, the Chaco will not last forever and the country's only uncontacted tribe will be wiped off the face of the Earth," Corry concludes.

"The government must stop Brazilian cattle ranchers from destroying its people's heritage before it is too late for the Chaco, and for the Ayoreo."