A friend recently sent we a copy of Sierra magazine (Jul/Aug 2013). In it, author Peter Frick-Wright tells of an archaeological investigation that was done at Lakeside Cave, at the southwestern corner of the Great Salt Lake. It seems the cave had been intermittently inhabited during the past 5,000 years:
In 1984, when archaeologist David Madsen had dug into [Lakeside Cave’s] sediment floor, he’d found the remnants of 5 million grasshoppers. Puzzled at first, he soon found bits of ‘hopper in some dried human feces nearby. The bugs had been for dinner, it seemed, but their sheer number sounded impossible. He assumed that catching grasshoppers was tedious work. How had they gathered so many?
The answer came a year later when some of Madsen’s friends who were hiking the shore of the Great Salt Lake came upon huge piles of grasshoppers washed up on the beach, sun-dried and seasoned by the lake’s brine. Madsen estimated that there were as many as 10,000 grasshoppers per foot of shoreline, deposited in windrows up to six feet wide and nine inches tall.
Then Madsen calculated the energy expended in gathering the grasshoppers and compared it with the energy they provided. Lakeside Cave dwellers would have been able to gather about 200 pounds of grasshoppers per hour, with bugs yielding 1,365 calories per pound. Even if he had somehow overestimated the rate of return by a factor of 10, he figured, the only thing as calorically rewarding as eating grasshoppers would have been finding 43 Big Macs stacked on the sand.
When Madsen removed the lake’s uncommon bounty from the equation, he still found that gathering bugs by more traditional methods–like herding them into ditch traps or streams and scooping them out–compared favorably to most forms of hunting.