Chaco War

The Chaco War was a major military conflict in South America. It lasted from 1932 to 1935.

The fighting was between Bolivia and Paraguay. They fought over the northern part of the Gran Chaco region. This area is also known as the Chaco Boreal. Many people believed this land was rich in petroleum. Because the Chaco is a semi-arid region, the conflict was called "La Guerra de la Sed," or "The War of Thirst."

Both Bolivia and Paraguay were landlocked nations. This means they had no direct access to an ocean. Bolivia had lost its Pacific coast to Chile in 1879. Paraguay had lost territory to Brazil and Argentina earlier. Control of the Paraguay River was very important. It would provide a way to reach the Atlantic Ocean for trade. Access to the ocean was vital for their economic development. The discovery of oil in the Andean foothills made the Chaco even more valuable.

The war had many complicated causes. One cause was a long-standing dispute over borders. Bolivia argued the land belonged to old Spanish colonial provinces. Paraguay argued they had occupied the land through ranching and forestry. There were also interests from international oil companies. Standard Oil supported Bolivia, while Royal Dutch Shell backed Paraguay. Some historians argue these companies caused the war. Others say the governments were not simply puppets of these companies.

Small clashes happened for many years before the full war began. In 1885, Bolivia founded Puerto Pacheco on the Paraguay River. A Paraguayan gunboat later evicted the Bolivians from that settlement. Both sides built small garrisons called "fortins." Tensions rose in 1927 when a Paraguayan officer, Adolfo Rojas Silva, was killed near the Pilcomayo River. This led to more violence in 1928 at places like Fortín Vanguardia and Fortín Boquerón.

The two armies used different types of weapons and strategies. This was the first war in South America to use modern weapons. These included airplanes, armored fighting vehicles, and machine guns.

Bolivia had a larger army and better equipment. They used Vickers-Berthier light machine guns and Mauser rifles. Paraguay had a smaller population but used an innovative fighting style. They focused on rapid marches and flanking encirclements to trap enemies.

They also captured Bolivian weapons to use for themselves.

There were major differences between the soldiers of each nation. Paraguay had a population of about 880,000 people. Bolivia had a much larger population of about 2,150,000 people. However, Paraguay mobilized its entire army for the fight. Most Bolivian soldiers were Quechua or Aymara peasants. They were used to living high in the Andes Mountains. The dry, hot Chaco was a very difficult environment for them.

The war was very costly for both countries. It was the bloodiest war in 20th-century South America. Around 2% of the Bolivian population was killed. About 3% of the Paraguayan population died during the conflict. The fighting finally ended at the Chaco Peace Conference in Buenos Aires. In July 1938, a peace treaty was signed. This treaty awarded three-quarters of the Gran Chaco to Paraguay.