Millie is athletic, agile, and never complains -- the perfect climbing partner for an adventure in the hills and gorges of the American West. He also happens to be a cat. 

Craig Armstrong, a climber and contributor to Backcountry.com, documented his journeys with Millie, whom he says he picked up at a shelter in Utah. Armstrong says that Millie “has all the qualities a good climbing partner should have.”

It’s a nice bonus that we enjoy the same kinds of climbing and prefer the same areas. I’m weak, and she doesn’t have opposable thumbs, so we tend to like similar routes: slabby tech routes that require more technique and balance than raw power. It makes planning trips pretty simple. She also gets along great with the rest of my friends in the climbing community. Everyone loves Millie—how could you not?

Armstrong’s Instagram is full of shots of his capable climbing partner; here are some of the best ones: