Brighty of the Grand Canyon (1966)

At the turn of the century in the Southwest Brighty the wild burro accompanies his friend a prospector named Old Timer on a hunt for gold A claim jumper robs the pair of their strike killing Old Timer in the process Brighty then sets out on a quest befriending a mountain lion hunter along the way to bring Old Timers murderer to justice in this drama based on the bestseller by Marguerite Henry