beast of burden vs transporter

beast of burden

noun
  • A draught animal, such as a donkey, mule, llama, camel, horse, or ox, that carries or pulls a load for the benefit of a human. 

  • Any domesticated animal trained to perform tasks for humans, such as a herding dog or trained falcon. 

transporter

noun
  • A conveyor belt that transports objects in a factory etc. 

  • A carrier. 

  • A long truck or lorry for carrying vehicles. 

  • A type of crane for loading or unloading a ship. 

  • A device that instantaneously transports, or teleports, a person or object. 

How often have the words beast of burden and transporter occurred in a corpus of books? (source: Google Ngram Viewer )