Deserts and limitations: lessons from prehistoric desert dwellers.

Author:Grossman, Richard

Living in the desert is challenging. We spent the week after Christmas in Baja, California, camping on the beach. Fortunately, our tents were comfortable and meals were cooked for us. But Pedro, a Baja native, gave us a glimpse into a very different past.

The afternoon was cool with sun shining through broken clouds and a rare rain in the offing. As we climbed up the steep, rock-strewn path we were careful to watch our step. Although vegetation is sparse, most of the plants wear spines or thorns for protection. A little stumble could result in a painful jab. Despite their armor, many desert plants are edible. Pedro assured us that the common prickly-pear cactus fruit tastes good, and even the pads are edible--after removing the spines.


We reached a cave that had been the winter home for a band of Pericu people, the extinct indigenous tribe of southern Baja. A small red ochre pictograph decorated the cave. We imagined a dozen people huddled in the chill admonishing their toddlers to stay away from the edge. A pile of shells lay below, showing that the Pericu enjoyed the ocean's bounty.

On top of the mesa we found their summer home. There was little to mark it except for another heap of shells and four round depressions in the rock. Grinding holes, Pedro commented. He then explained that there is a type of manna--the pitahaya fruit--that ripens in late summer. It grows on the organ pipe cactus (pitahaya dulce) that resembles a clump of spiny fingers pointing skyward. The size of a tennis ball, pitahaya fruit has the color and a bit of the flavor of watermelon. Although rich in energy, the tiny seeds pass through without being digested.

European missionaries recorded that the indigenous peoples were hungry except during the brief pitahaya season--perhaps wishful thinking on the Europeans' part. Lacking any means of preserving fruit, how could people prolong this short season of plenty? Baja natives came up with an unlikely solution.

The indigenous people developed a system to harvest the nutrition in pitahaya seeds that disgusted missionaries. While enjoying the abundance of the harvest, people collected their poop in special places. When it had dried, the seeds were separated, washed, and then pulverized in those circular rock depressions. After grinding they make an edible paste high in fat. Their "recycling" of calorie-rich pitahaya seeds illustrates how desperate they must have been to get enough nutrition.


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