The Inca Mailmen
The roadrunners were the mailmen of the Inca empire. They were allowed to run on the roads. They worked by a relay system. One roadrunner would carry a message about a mile down the road and tell it to the next roadrunner. Most messages were oral. Some were sent by quimpus, the knotted language of the Inca.
Accuracy was important. If you messed up a message, you were killed. Speed also was important. As a runner approached the next runner, he would blow on a conch shell to let the runner know he was coming.
Runners carried no weapons. If they were attacked by a wild animal, they fought by hand, or ran away, or died. It was a dangerous job. But runners did not have to work in the fields.