Donkeys' tough digestive system is somewhat less prone to colic than that of horses, can break down near-inedible vegetation and extract moisture from food very efficiently.
Donkeys have a notorious reputation for stubbornness, but this has been attributed to a much stronger sense of "self preservation" than exhibited by horses. Likely based on a stronger prey instinct and a weaker connection with man, it is considerably more difficult to force or frighten a donkey into doing something it perceives to be dangerous for whatever reason. Once a person has earned their confidence they can be willing and companionable partners and very dependable in work.
Although formal studies of their behaviour and cognition are rather limited, donkeys appear to be quite intelligent, cautious, friendly, playful, and eager to learn.