Ceder Wright and Alex Honnold are basically explorers for a living — the two travel together to crazy places around the world and record their journeys for National Geographic. On a recent trip through the American Southwest, they picked up an unexpected addition.

YouTube/NationalGeographic

The two men had stopped somewhere in the desert for a bathroom break when they spotted a tiny, shivering puppy curled up in an old tire. They couldn’t just leave him there, so they picked him up and took him in.

Of course, they weren’t prepared for raising a puppy on their trip, so they fed him string cheese and let him drink their water.

YouTube/NationalGeographic

The duo named him Sufferpup … after the name of their grueling expedition through the desert, Sufferfest.

He quickly became the unofficial mascot of their trip, trotting along after the men everywhere they went.

YouTube/NationalGeographic

As they traveled, the little puppy grew bigger, stronger and happier. And at night, Sufferpup curled up inside an empty box of beer.

YouTube/NationalGeographic

After the expedition was over, Sufferpup was adopted by an awesome family in Colorado. But Wright and Honnold still go back to visit their little adventure buddy — even though he’s a LOT bigger now.

YouTube/NationalGeographic

Watch the whole adorable video here: