Steep slopes of recovery

Alejandro Espinosa was nervous. It was his first time searching for bighorn sheep in the wild. Espinosa, then a graduate student studying wildlife biology at the University of Nuevo Leon in Mexico, was climbing a steep and dangerous mountain known locally in the Sierra del Viejo of Sonora as "the Wall." After more than an hour of difficult hiking, he and his teacher, Luis Tarango, had reached a narrow cliff. A misstep here might have sent either or both of the men tumbling hundreds of feet down the sheer mountain side.

At that moment Espinosa noticed his legs were shaking. ...