Retired Big Bend National Park biologist Raymond Skiles spent a lot of time hiking the desert and mountains in the 1,252-square-mile park during his tenure. One of his favorite routes followed a ridge near the Rio Grande, where ocotillo dot the rocky limestone and the high ground offers views of the river and Sierra del Carmen mountains. For years, he enjoyed spotting various cacti along the way, including living rock cacti, a small spineless plant that blends in with the rocks. But around 2006, something curious started happening.
“On a walk one evening, I noticed a small pit, maybe 6 inches deep and wide,” Skiles says. “Then another, and another. Then dozens over a few hundred yards. I realized I was no longer seeing any living rock plants. They were all gone. It was clear that someone had walked that route digging them up.”