[4] The Piedras is the longest tributary of the 1,347 km long Madre de Dios River and more than 99 percent of its drainage is in the Amazon lowlands, below 400 meters.

One of the most notable rubber barons in the Las Piedras area, was Carlos Scharff, who enslaved and exploited the local native populations to extract latex.

[2] The Masco-Piro live on the tributaries of the Manu, Los Amigos, Las Piedras, and Tahuamanu Rivers (Castillo 2004).

These semi-nomadic groups are believed to move seasonally between the headwaters of the Manu, Alto Púrus, and Las Piedras rivers.

It remains unclear what provoked the attack, but various proposals have been put forward, including increasing threats by drug traffickers and loggers and unusually cold weather related to recent climate change.

[15] At the time, researchers recorded more than $5 million USD worth of wood traveling to the local market in Puerto Maldonado and that in one month the logging camps on the Piedras River consumed more than 2,000 mammals and more than 2,000 birds.

[15] More recently, the paving of the Interoceanic Highway has put increased pressure on the forests, wildlife, and indigenous communities of the Piedras region.

Recent changes to forestry laws are thought to be affecting the increased amount of wood being harvested in Brazil nut concessions in Madre de Dios.

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