Pack animals are animals that are used to carry goods and supplies. Common pack animals include MULES, ASSES, llamas, BURROS, OXEN, WOLVES, and rats. MULES are a hybrid of a horse and a donkey, and are known for their strength and endurance. ASSES are related to horses and donkeys, and are also known for their strength and endurance. Llamas are a domesticated species of South American camelid, and are often used as pack animals in the Andes Mountains. BURROS are small donkeys, and are used as pack animals in the southwestern United States. OXEN are domesticated bovines, and are used as draft animals in many parts of the world. WOLVES are wild canines, and are sometimes used as pack animals in some parts of the world. Rats are small rodents, and are sometimes used as pack animals in some parts of the world.