My professor of Geology at Rutgers use to tell me stories of his hikes down the Grand Canyon. More than one of his students finished the trip on the back of a mule.
My wife and friends did the mule ride down to an over night stay at phantom ranch lodge. Mule have 200lb limit. Did my best to keep above that number so could not go! I am not trusting my life to some Mule. Many people hike the trails down to river. Meanwhile some cannot make return trip so the mules have to be employed to do a “drag out” as the guides call it.