In part owing to its sparse landscape and unreliable rains, the area's fauna rather resembles much of neighboring Patagonia's. Perhaps the most common natural inhabitant to the region is the "ñandú", or, Darwin's rhea. Nearly ubiquitous to the region in the early 19th century, vast herds were often observed at the time and, indeed, they and their eggs had for centuries provided the Puelches and the area's other indigenous peoples with much of their protein needs. Targeted during successive genocidal campaigns between 1830 and 1880, however, these inhabitants lost most "ñandús" to massacres by Argentine armies, who believed that in so doing, the indigenous tribes could be starved into surrender.