Suelo is 48, and he doesn't exactly have a 401(k). "I'll do what creatures have been doing for millions of years for retirement," he says. "Why is it sad that I die in the canyon and not in the geriatric ward well-insured? I have great faith in the power of natural selection. And one day, I will be selected out." Until then, think of him like the raven, cleaning up the carcasses the rest of us leave behind.

Check out this video of Bryn Mooser and athlete Haley Ashburn slacklining in Moab, Utah: