donkey, mule

Definition:

A donkey is a four-legged work animal, similar to a horse, but smaller and with longer ears.

A mule is the sterile offspring of a male donkey and a female horse.
Mules are very strong animals and so they are valuable work animals.
Both donkeys and mules are used for carrying burdens and people when traveling.
In Bible times, kings would ride a donkey in times of peace, rather than a horse, which was used for times of war.
Jesus rode into Jerusalem on a young donkey a week before he was crucified there.