The holes in the limestone are places where Native Americans ground whole mesquite pods into flour, pounding them to powder with a blunt piece of mesquite or a suitable rock and creating the depressions visible here. Native peoples in this region traditionally collected and used many plants for food, medicine, clothing, tools, and other purposes, and tribal members still maintain a strong interest in caring for these plants and retain the right to gather on their ancestral lands. Mesquite pods were an especially important food source for native desert peoples, and scientists now know mesquite flour is rich in calcium, magnesium, potassium, iron, zinc, and the essential amino acid lysine. Wild grapes commonly grow by springs throughout the Refuge and were traditionally eaten raw or dried and stored for year-round consumption.