Identification. The name "Mashco" is of unknown origin, and in the Peruvian departments of Cuzco—in the tropical zone toward the northeast—and Madre de Dios, the word has been synonymous with "assassin" or "criminal." The various Mashco factions identify themselves as "Xarangbütn" (human beings), but they also call themselves by some toponym, which refers generally to a river on which they live.
Location. The Mashco are located between 71°35′ and 69°23′ W and ll°35′ and 13°40′ S. This is an inland area which, descending abruptly from the Andean mountain ranges, leads into the northwestern portion of the Amazon Basin. The river system of the Madre de Dios has an intricate net of tributaries in the Mashco area, with numerous streams and some rivers with a copious flow of water. The boundaries of Mashco territory are formed by the Andean slopes below the mountain line of Tres Cruces-Marcapata, the western border of the Kosñipata Valley, the Río Madre de Dios up to where it joins the Río Inambari, and the latter in the direction of Marcapata, including a stretch of the Río Manu. From a climatic and phytogeographic perspective, this area is characterized by a subtropical strip of rain forest, monsoon forest, and cloud forest. The climate is typically tropical, divided into a dry season and a rainy season. The former—between May and October—is characterized by limited precipitation and icy winds coming from the south, which, intensifying during July and August, lower the temperature considerably. When these winds blow, there is a heavy downpour, which brings with it an increasing abundance of water in rivers and streams, but these diminish rapidly after a few days. The humid season follows, with heavier rainfall—over 200 centimeters between November and April. The water level in rivers and streams remains at several meters above normal.
Mashco territory can be divided into two clearly differentiated areas: the high jungle, or montaña , and the low jungle. The former occupies the greater part of the area, including the sources and a large portion of the median courses of the rivers that descend from the western chain of the Andean mountain ranges. It is characterized mainly by soft hills, the last spurs of the aforementioned mountain range. The lower jungle is formed by the course of the Madre de Dios, from Manu and the lower stretch of the Inanbari to Puerto Maldonado, with an elevation of 200 meters, whereas the Kosñipata Valley reaches an elevation of 700 meters.
Demography. An estimated 6,000 Mashco inhabit an area of around 24,910 square kilometers, which, at the beginning of the twentieth century, had a population density of 0.24 inhabitants per square kilometer.
linguistic Affiliation. At first the Mashco language was classified as pre-Andean Arawak, together with Piro, Machiguenga, and Campa. Later studies showed that it was an isolated stock with a large number of Arawakan elements. That is why the Hararákmbet Language Family includes several dialects like Araseri, Amaracaeri, Wachipaeri, Toyeri, and Zapiteri—names, which, at the same time, designate various factions.