"Way Back When"

Good Morning ,
Down South when your out for a quite drive in the country you may pass a field with cattle grazing. Along side or on top of the cattle are their trusted friends the cattle egrets. Even in the ocean a whale or shark will swim by with a buddy fish riding along. They live off the insects or parasites the host collects. It all started somewhere back in prehistoric times .....in the human world what would they be called ....Hmmm.....maybe car salesmen, politicians...no advertiser.
Have a great day and a side of cartoons...Robbay